Researched & Compiled by Sandra L Bridges
Assisted by Penelope C Inan
Clay statues of hairless dogs have been found in the thousands in burial sites in Mexico. Highly collectible, these ancient artifacts illustrate the extraordinary importance that this dog held in ancient society. Columbus mentioned encountering strange hairless dogs in his 1492 New World journals.
THE NEXT ACCOUNT of the Xoloitzcuintle (“Mexican Hairless Dog”) is by the European, Glover M. Allen in his “Dogs of the American Aborigines”, 1920, and seems to be that of Francisco Hernandez, (1514-1578):
“A dog of medium size, rather heavily built, and long bodied in proportion to its height; ears large and erect; tail thick, drooping or carried nearly straight behind; hair nearly absent except for a few coarse vibrissae and generally a sparse coating on the tail, particularly near the tip sometimes a tuft on the crown.”
IN 1785, THE NATURALIST, Buffon, reports the following:
“The first and largest of these American dogs is called Xoloitzquintli. He is often three cubits long ( ); and what is remarkable, he is totally destitute of hair, and only covered with a soft, close skin marked with yellow and spots.”
The Xoloitzcuintli is now known to be one of the world’s oldest and rarest breeds, with statues identical to the hairless variety dating back over 3,000 years. These clay and ceramic effigies have been found in tombs of the Mayan, Colima and Aztec Indians. Xolos were considered sacred dogs by the Aztecs (and also Toltecs, Mayans and some other groups) because they believed the dogs were needed by their masters’ souls to help them safely through the underworld, and also they were useful companion animals. According to Aztec mythology, the god of lightning and death, Xolotl, made the Xoloitzcuintle from a sliver of the Bone of Life from which all mankind was made. Xolotl gave this gift to
Man with the instruction to guard it with his life. In exchange, it would guide Man through the dangers of Mictlan, the world of Death, toward the Evening Star in the Heavens. The Aztecs deeply revered the Xolo and believed the breed to have mystical healing abilities.
Indeed, the dog owes its name to the Aztecs, who named the breed after Xolotl. This root word was then co-joined with the word for dog, 'itzcuintli' to form the name Xoloitzcuintli (pronounced 'Show-low-eet-squint-lee'). For the Aztecs as well as several other pre-Columbian civilizations, the Xolo dog possessed not just healing properties for the physical body but also for the spirit. There were actual dogs buried alongside their caretakers, and statues of these dogs were placed in tombs to ritualisticcally serve the same purpose. The famous “Colima dog statues” are the premier example of this. A dog statue from the Colima tombs
Always prized for their loyalty, companionship and intelligence, they are also credited with curative and mystical powers. Because they were believed to be favored by the Aztec god Quetzalcoatl, sacrifices of the dogs were sometimes dedicated to him. At one time, Xolos were prevalent throughout Mexico and large portions of Central and South America. Most likely, early forerunners of the Xolo originated as spontaneous hairless mutations of indigenous New World dogs. Hairlessness may have offered a survival advantage in these tropical regions. Indigenous peoples of these areas valued the Xolos for their loyalty, companionship and intelligence, as well as their curative and mystical powers. In poor, rural areas, Xolos were eaten when other food was not available.
After the Spanish Conquest of the Aztecs, the breed population in its native lands dwindled and was kept alive only by secluded Indian tribes in remote parts of Mexico and South America. The breed did not receive any official notice in Mexico until the 1950s. The FCM, founded in 1940, was not prepared to declare the Xolo an official purebred at that time.
According to breed historian Norman Pelham Wright, author of The Enigma of the Xoloitzcuintli, Xolos first began to turn up at Mexican dog shows in the late 1940s. While it was recognized that these were indigenous specimens of a native breed, interest in them was minimal at that time. Reliable information was scarce and, with no national breed club, no standard existed by which to judge them. ¯
Within a decade, however, the FCM realized that the breed would be extinct if drastic action were not taken to save it. This led to the widely publicized “Xolo Expedition of 1954”. With the official sanction of FCM, Wright and the British Chihuahua expert Hilary Harmer, along with the Archduchess Felix of Austria, better known as the Countess Lascelle de Premio Real and a team of other Mexican and British dog authorities, set off to discover if any purebred Xolos still existed in remote areas of Mexico.
We include the following information, “right from the horse’s mouth”, as it were.
Excerpts from:
“A Guide to Mexican Mammals and Reptiles”
by N. Pelham Wright, F.Z.S.
(Published in 1965 in Mexico)
“. . . .there are two types, or breeds, of Dog that have evolved in Mexico and are to be regarded as typically Mexican. It so happens, moreover, that neither is fully understood, and that a considerable amount of nonsense has been written about both.
(NOTE: On the pages following this excerpt appears the article with the ‘Official Standard for the Mexican Hairless’ from the 1935 Official A.K.C. publication, Toy Dogs: the Breeds and Standards as Recognized by the American Kennel Club. This article could be said to be some of the aforementioned “considerable amount of nonsense” written about what was a most likely a Chihuahua/Toy Xolo crossbred. These small, hairless crosses were bred and sold in numbers to Americans near the U.S.-Mexico border as a “Mexican Hairless”. They could NOT have been the true Xoloitzcuintle, as they were found in only the toy variety and resembled nothing more than a hairless Chihuahueño. It seems obvious today that this diminutive dog could not have been the ferocious animal needed to save his master from the “fiendish crocodiles” encountered on the journey of the dead to be ferried across a subterranean “infernal river”.)
. . . .the other is the Xoloitzcuintli, an animal without hair on its body that in hardly any way resembles the chihuahueno.
Seemingly, there is confusion with respect to not only the names of these animals, but also their origin and history.
. . .some years ago Colonel and Mrs. Harmar, enthusiastic chihuahueno breeders then living in Mexico City, briefly explored parts of Chihuahua, seeking traces of the Dog there.. . .
Photo above from the actual 1965 “Guide”
Xoloitzcuintli
The second Dog – more important and much more typical of Mexico – is called xoloitzcuintli, sometimes now abbreviated to Sholo. It is an extraordinary animal, about which I was once induced to write a book, ‘El Enigma del Xoloitzcuintl’i.
Together with other undefined types of Dogs, the sholo was the first domestic animal in North America. Its forebears, already with some unexplained biological tendency toward nudity, must have accompanied early man from Eastern Asia across the Bering Straits. Its nearest relative is another form of naked Dog formerly known in Manchuria, and possibly still present there.
Zoologists like Brehm complicated the issue of its classification by giving it Latin names such as Canis caribbaeus, in Yucatan, as though it were a natural, wild species, whereas it was never a wild animal but merely an unconventional form of Canis domesticus. More recently, zoologists have stated categorically that there has been no wild canine in America which could have been the progenitor of any domestic Dog. This is tantamount to saying that all Dogs found with American Indians when the Europeans arrived must have been descendants of those brought from Asia by prehistoric immigrants.
There is a wealth of evidence that, before the Conquest, the Indians in Mexico held the sholo in great esteem; that it had a religious significance, was used medicinally, and even eaten; and that efforts were made, with the help of a depilatory unguent, the recipe for which has been lost, to maintain its nude state. The Nahuatl name xoloitzcuintli means “he who snatches his food with teeth sharp as obsidian (i.e., Dog), and who is the representative of the god Xolotl.” This deity was the god of twins and monsters, being himself the twin brother of Quetzalcoatl, god of life and civilization.
The animal’s ancient religious role is illustrated by the belief, widespread even today amongst certain rural groups in Mexico, that the dead need to be ferried across at least one subterranean infernal river, before their souls can reach “the promised land.” Only black Dogs were thought to be able to do this, and to save their masters from the fiendish crocodiles encountered on the journey. Therefore, the Dog of the deceased was killed and buried with him. The sholo, normally black or at least dark gray, can be assumed to have been the type of black Dog favored for this ferrying operation.
Medicinally, the sholo’s value is logical in the extreme. Certain simple ailments can be alleviated by the use of a hot-water bottle. The hot, naked – and consequently flealess – body of a xoloitzcuintli makes a fine substitute and, even today, countrywomen in Sinaloa, when they feel indisposed, go to bed with a sholo to warm their stomachs. Among older people in the Balsas River Valley, state of Guerrero, it is believed that possession of such a Dog protects them from colds and other ailments.
Early Spanish historians reported that dog flesh was relished by the Indians, who considered it a great delicacy. Bernal Diaz del Castillo, for one, mentioned hairless Dogs among the innumerable exotic food items the conquerors found for sale in the fabulous marketplace of Tlatelolco. It is even recorded that, in the 16th century, many Spaniards acquired a taste for dog flesh. The sholo is usually called pelon mexicano in popular parlance. The Mexican Kennel Club finally adopted the present name, in complex circumstances, for details of which the reader is referred to his author’s book on the subject, mentioned above. It is not identical with the animal called Mexican Hairless¯¯ in the United States, which was probably never an established breed, but a creature of unstable form, bearing little resemblance to the traditional xoloitzcuintli.
Since the above-mentioned book was published, I have had correspondence with a geneticist which undoubtedly has a bearing on this animal’s curious characteristics, even though further study of the matter may indicate some local deviation from the law concerning hairlessness that has been expounded by certain geneticists.
In brief, the law is that there is a dominant gene for hairlessness, and that all hairless dogs have one, as well as a counterpart gene, for a normal coat. Litters from hairless matings allegedly consist of 25 percent with normal coats (homozygous), 50 percent hairless (heterozygous), and 25 percent still-born, the latter having inherited the dominant gene from both parents. It is stated that selective breeding cannot change these proportions, with the result that it will, clearly, never be possible to regard hairless dogs as genetically stable, for “throwbacks” with normal coats will persist forever. The experience of some xoloitzcuintli breeders in Mexico since 1955, however, including my own, does not seem to confirm the foregoing; only a conscientious long-term study of the matter appears likely to determine whether or not the xoloitzcuintli constitutes an exception to the law. (N.B.: Recent scientific studies have confirmed that the double dominant hairless gene (HH) is, in fact, embryolethel, or deadly. All species, i.e. hairless mice, moles, cats, etc. appear to be thus affected.)
In 1955 I was invited by the Mexican Kennel Club to take steps to preserve the sholo which, it was suspected, was threatened with near extinction. At that time, only one Dog that was felt to conform to type was registered with the Club. Now, ten years later, more than 70 specimens are registered. A detailed standard for the breed was evolved and published. ¯Refer to his original (1955) standard printed later in this article.
Elsewhere I have reported on an expedition to a certain village in a tropical area of Guerrero which brought back to the capital the first good specimens for breeding purposes. Later, I returned to the village for more animals, and the majority of the registered sholos living today, at least those belonging to Dog fanciers, are descendants of the specimens I obtained from the Balsas River Valley in the 1950’s.
The xoloitzcuintli is, indeed, a very unusual Dog, unique in many ways. It has three physical peculiarities that no biologist has yet explained: an almost invariable absence of teeth between the foremost molars and the incisors; a body temperature several degrees higher than that of an ordinary Dog; and the trait of sweating through the skin, particularly on the underpart of the body, rather than through the tongue, by panting after exertion, as other Dogs.
Having owned one of these animals for about two years, I can add that they also present many pecularities of character. My wife and I filled several note books with observations of our young sholo’s behavior. These notes touched on her attitude toward other animals, and to fire; her dignity, charm and gaiety; her complete dependence, combined with utter disregard of her owners’ wishes; her cleanliness and intense domesticity, as opposed to a sort of inherent vagrancy which resulted ultimately in her disappearance (we never found her again); her insatiable appetite and her cunning in stealing food, as though she were balancing the account of generations of undernourished forebears.
Endearing or infuriating, our sholo, Dona Ugalde, was a very strong little character, and there is reason to believe that all these Dogs are of her stamp.”
Eventually, Wright located and brought back sufficient numbers of good Xolos and it was these dogs that formed the foundation of Mexico's program to revive the breed. A committee headed by Wright authored the first official standard for the breed. (¯See “Standard for the Large Xoloitzcuintli” below.) The Xoloitzcuintli breed was first registered in Mexico in 1955. When on May 1, 1956, the “Standard” for the breed was adopted, the Xolo was finally recognized in its native land and is now the designated “Official Dog of Mexico”. With Mexico a member of the FCI, this gained the Xoloitzcuintle worldwide recognition, too.
¯STANDARD FOR THE LARGE XOLOITZCUINTLI Adopted By The Mexican Doglovers' Association (A.C.M.) On 1 May, 1956
1. GENERAL APPEARANCE
The dog should measure, as an adult, more that 30 cms. high at the "cross" (base of the neck), and the best measure a little less that 50 cms. It should have a harmonious overall appearance, gracile movements and large legs.
2. HEAD
Cranium: viewed from above, should be wide and strong. The line of the cheeks ought to smoothly narrow toward the base of the snout, without being brusque. Seen in profile, there ought to be a slight curve in the upper line. The frontal-nasal depression ought not be very pronounced, given that the planes defined by the snout and the cranium should not be greatly separated.
Snout: bony, of a proportion somewhat larger than the longitudinal width of the cranium. Seen in profile, it is similar to the wedge of the acute line, but neither course nor weak, but rather proportionate to and in harmony with the cranium.
Ears: large, expressive and elegant, measuring up to 10 cms. in length, and thin, reminiscent of the ears of a bat. Laterally inserted into the cranium, and raised when in a state of alert. In this position the ears ought to be between 50 and 80 degrees from horizontal.
Eyes: of medium size, somewhat almond-shaped, neither too close together nor too separated, neither deep-set nor bulging. The color of the eye ranges from yellow to black, and dark colors are preferred. The two eyes are always the same color. The expression is one of intelligence and liveliness, and transmits the noble and faithful temperament characteristic of the animal. The eyelids ought to be dark in dark animals, and may have pink or brown spots in animals with less pigmentation.
Teeth: the mandible closes like a pair of scissors. Lower or upper prognathism will be penalized. May lack all premolars. The absence of an incisor will not be penalized, but preference will be given to those with all incisors.
Nose: dark in dark animals, pink or brown in animals of those colors.
Lips: pursed, perfectly covering the teeth. With neither superior nor inferior blubber-lips.
3. BODY AND LIPS
Neck: raised, proportionately large, slightly arched in the cervical line, flexible with the grace of an antelope. Without wrinkles or a double chin. Inserted in the thorax in the part called the cross. Narrow at the base of the cranium and gradually widening towards the connection with the thorax.
Chest: deep, developed to the height of the elbows.
Ribs: well-developed, without interfering with the movements of the front limbs.
Belly: muscular, tight.
Shoulders: straight loins, ending in a rounded rump. Animals that are overly arched are undesirable. The ratio of the length of the body to its height ought to be 9 to 10.
Front limbs: the legs, seen from the front, ought to be straight and proportionate, of sufficient length to enable a long and elegant step, in proportion with the size of the dog. As far as the shoulders are concerned, the union of the shoulder blade with the humerus ought to produce an angle close to 45 degrees. Firm elbows that do not stick out.
Hind quarters: the muscles should be firm, wide, and give the impression of potency. The angles formed by the unions of the pelvis and femur, femur and tibia, tibia and shank or hock ought not be very obtuse, but rather should show the angles indispensable for the wide and free movement of these extremities. Seen from behind, the hind quarters ought to be completely straight. Bovine, cloven feet will be penalized.
Feet: like a hare's, with digits drawn in. Black nails in dark animals; light colored nails are acceptable in animals with less pigmentation in the feet.
Tail: long and fine without knottiness, prolonged to the shank, and narrowing towards its tip.
Hair: The principle characteristic of this dog is the total absence of hair, though a tuft of rough, short, not very dense hair atop the cranium is common. This never ought to reach the length or softness of the long lock of the Crested Chinese Dog, or "Tai-Tai". Similar hair is also common on the end of the tail, but its presence ought not change the profile of this appendage. The total absence of hair in these regions should not be penalized.
Skin: Smooth and soft to the touch, especially those parts less exposed to the sun. Accidental scars should not be penalized, as the skin of this animal is by nature sensitive. The skin feels hot to the touch, given that the normal temperature is approximately 40 degrees centigrade, this being one of the peculiarities of the animal. Its skin sweats, especially the lower parts, and for this reason it rarely or never sticks out its tongue and pants like other dogs.
Color: A uniform color, from dark bronze, gray, dark gray, or black, is preferred, though animals with brown or pink spots or areas without pigmentation are also tolerated. Discoloration on an exaggerated scale however is undesirable. If there is hair on the head or tail it ought to be black in dark animals; in light-colored animals hair of any color in harmony with the overall coloration is tolerated.
4. ADDITIONAL OBSERVATIONS
A good adult is a rather silent and tranquil animal, which only barks, growls and whines upon provocation—something which by no means implies a sad or cowardly character. It should be happy, noble, alert and intelligent. Neither aggressive nor timid animals are desired. The puppies are different from the adults in appearance, given that they are flat-nosed and short-legged, and frequently noisier than the adults. Their characteristic traits assert themselves as they develop.
5. TRAITS ESPECIALLY UNDESIRABLE
Timid character, ears that cannot lift up entirely, exaggerated discoloration, hair growing in areas other than the cranium or tail, skin that is exaggeratedly loose, the presence of fetlocks, monorchidism.
6. DISQUALIFIED
Hanging ears, like a hound's, cut ears, cut tails, albinos, unilateral cryptorchidism.
The foregoing was authored in 1955 by the ITZCUINTLE COMMITTEE OF THE MEXICAN DOGLOVERS' ASSOCIATION, A.C., chaired by Norman Pelham Wright.
Brief bio of Norman Pelham Wright, from the outside back cover of A Guide to Mexican Mammals & Reptiles, by Norman Pelham Wright, 1960
“Born and educated in England, as a young man Norman Pelham Wright traveled, studied and worked in Germany, France and Spain. After serving with the British forces in Europe during World War II, he was appointed Military Attache’ in Mexico and Central America.
Later, he became director of the British Broadcasting Corporation in several South American countries and, in 1952, established permanent residence in Mexico City. Here he first managed the British Chamber of Commerce and now, among other activities, edits its monthly magazine, Intercambio.
A Fellow of the Royal Geographical Society and of the Zoological Society of London, he is also a lifetime honorary member of the Mexican underwater exploration society, CEDAM. The author of four other books about Mexico, he possesses an active enthusiasm for orchid hunting, a life-long interest in animals and a growing habit of writing on both subjects.”
The Xoloitzcuintli was actually first registered with the American Kennel Club (AKC) from 1887 to 1959 as the “Mexican Hairless” breed, but was dropped due to insufficient numbers of dogs being bred and registered. The photo with the “Mexican Hairless” chapter from the AKC 1935 “Toy Dogs” should make it completely clear that this breed was in NO WAY a true Xoloitzcuintli, simply a hairless Chihuahua.
MEXICAN HAIRLESS
(Following article and standard from TOY DOGS Recognized by the American Kennel Club, 1935)
One of the most curious and distinctive breeds, the Mexican Hairless also is one of the oldest varieties of pure-bred dog in the world. Its hairlessness long has been one of the mysteries balking the most intensive investigation of scientists. The theory has been advanced that the lack of hair has been brought about by the temperature and the climate of the country in which the breed has existed. If this is true, the process of evolution must be extremely slow – for long-coated dogs have been known to exist under similar conditions for thousands of years.
Hairless dogs exist in many other parts of the world besides Mexico, and the theory which finds most acceptance – especially among Mexican authorities – is that this breed now found in relatively large quantities in the country below the Rio Grande is a descendant of the hairless dogs of China, where two somewhat similar breeds are known.
According to Sr. Blinde, the Mexican Hairless, or Biche, was established in Mexico when the Aztecs founded the Empire of Tenochtitlan in the Valley of Mexico. This tribe of Indian conquerors had brought the dog with them from Asia, crossing over the land bridge to Alaska at what is now the Bering Strait.
Just when the Aztecs migrated from Asia is a matter of some doubt, and there even is a supposition that the migration may have been in the opposite direction. However, the more reasonable one is that the Aztecs came from Asia. Had id been the other way, the hairless dog would have undoubtedly have been discovered in other parts of North America, and it would not be found so often in different parts of Asia and Africa.
The Chinese Crested bears striking resemblance to the Mexican Hairless, and there is another hairless breed in China that is not so far removed from the Mexican variety. Then there is the Rampur dog of Southern India, likewise of the same general type. Another is the African sand dog, and somewhat similar dogs are found in Turkey, and in Japan. The South American dogs, of course, are regarded as closely related to the Mexican Hairless. The identical dog is found as far south as the Peruvian lowlands.
In Mexico the hairless dog is called commonly the “Biche,” and this another bond that links it to the old Indian civilization, for the word is an Aztec one meaning “naked.”
Indications are that when the Biche started its travels with the Aztecs it was a much larger dog, believed to have been about the size of a small foxterrier. Yet it always was a light-boned animal, built on racy lines that might point to a very ancient descent from the greyhounds. Quite naturally the Aztecs could not take a great many dogs with them, and consequently the inbreeding brought a reduction in size.
The old legends that still persist, today, that the Mexican Hairless is possessed of healing qualities probably had their inception back in the Aztec days. In fact, this supplies a motive for an Indian people to have preserved this breed of dog through the generations. There is little or no reason to believe these stories, aside from the fact that heat often has a curative effect in certain instances, and the skin of this dog is hot to the touch. But from that simple basis grew many widespread beliefs, and in the time the ignorant were of the opinion that a person suffering from almost any disease would be cured of it if a dog of this breed were held close to the body. Specifically, one suffering from “rheumatism” could be relieved of it if the dog were placed at the feet.
The Mexican Hairless as recognized in the United States is a small, toy specimen, found in a variety of colors. Sometimes the skin is of a mottled nature, but that is less desirable. There is no hair on the body, but a slight fuzz on the top of the head, and sometimes a few hairs on the tail.
The great centers of the breed in Mexico are on the West Coast; Mazatlan, and Durango, but there are also relatively large numbers in the City of Mexico. Outside interest in the dog undoubtedly has proven a stimulus to breeders in Mexico, and the specimens of modern time are being bred to a high state of perfection.
DESCRIPTION & STANDARD OF POIINTS:
The Mexican Hairless is a small, active dog, about the size of a small Fox Terrier, symmetrical and well proportioned, with rather broad chest and ribs and with slender legs.
Head – Should be slender and skull narrow, cheeks lean, muzzle long and pointed. There should be a tuft of coarse hair on top of the skull, in the center but a bit forward, in some cases shadowing the brow.
Eyes – Should not be too deep set but balanced and not bulging – eye rims pink or
dark and the eyes themselves hazel, yellow or dark.
Neck – should be of good length, slender and well arched into flat shoulders and the chest rather broad, legs fairly long and slender, ribs well rounded and chest rather deep.
Back – Should be level, rump slightly rounded.
Skin – Smooth and soft, not wrinkled, any color, hot to touch, no hair whatever.
Muscles and sinews well developed. A nervous tremor of muscles and sinews is characteristic like that of a nervous race horse.
Feet – Should be hare feet, nails black in dark skin or pale in pale skin dogs.
Tail – Long, smooth tail, carried out similar to that of Manchester Terrier. A little fuzz or hair on lower half of tail permitted.
Absence of tuft on top of the head is undesirable but not a disqualification.
Cut or broken ears or tail are disqualifications, likewise a fuzz or any hair, except as above described.
Since 1997, however, the Xolo has been recorded in the AKC Foundation Stock Service for rare breeds. In January of 2011, the Xoloitzcuintli, ancient canine molded by environment and function, joins his fellow primitive pariahs, the Basenji, the Canaan Dog, the Ibizan hound and the Pharaoh hound, among others, in the A.K.C. conformation show ring to compete with full recognition. In the U.S., all three sizes and both coats will be judged together as one breed in the Non-Sporting Group.
The Xoloitzcuintli is currently registered by the Canadian Kennel Club in the Non-Sporting Group for the Standard and Miniature and in the Toy Group for the Toy Xolo.
In the F.C.I., the Xoloitzcuintli is judged in the Primitive and Spitz Group, recognizing their ancient origins.
Source: http://www.xoloitzcuintliclubofamerica.org/yahoo_site_admin/assets/docs/XOLO_HISTORY_MAC.244131811.doc
Web site to visit: http://www.xoloitzcuintliclubofamerica.org/
Author of the text: indicated on the source document of the above text
If you are the author of the text above and you not agree to share your knowledge for teaching, research, scholarship (for fair use as indicated in the United States copyrigh low) please send us an e-mail and we will remove your text quickly. Fair use is a limitation and exception to the exclusive right granted by copyright law to the author of a creative work. In United States copyright law, fair use is a doctrine that permits limited use of copyrighted material without acquiring permission from the rights holders. Examples of fair use include commentary, search engines, criticism, news reporting, research, teaching, library archiving and scholarship. It provides for the legal, unlicensed citation or incorporation of copyrighted material in another author's work under a four-factor balancing test. (source: http://en.wikipedia.org/wiki/Fair_use)
The information of medicine and health contained in the site are of a general nature and purpose which is purely informative and for this reason may not replace in any case, the council of a doctor or a qualified entity legally to the profession.
The texts are the property of their respective authors and we thank them for giving us the opportunity to share for free to students, teachers and users of the Web their texts will used only for illustrative educational and scientific purposes only.
All the information in our site are given for nonprofit educational purposes