The mold is like a jacket or hood, separated from the model by just the thickness of the clay. Model and jacket are given a coat of shellac and one of oil, then are put back in position and the space between them filled with glue The glue hardens to form a mold within the plaster jacket, the model of the head having been removed. [The photographs illustrate the process in connection with three different busts.] A glue mold is firm enough to give an accurate cast, yet yielding enough to allow its removal from about the cast. however many undercuts the plaster surface may present 27 during the age of land connection of the two continents. Interest has centered also in an investigation of the tribes of the Southwest and of the islands of the Pacific with reference to establishing possible connection between the Old and New Worlds at this point through Ethnology draws many conclusions from skull study but these results must of necessity be incomplete as compared with records. based on casts from life which give perfect Mr. James C. Bell, expert worker in plaster, making a glue mold of an Indian head. Glue is poured into the funnel, the lower end of which opens into a half-inch space between the original model and the plaster jacket fitting over it. As the glue rises in this space about the model, holes previously cut in the jacket to allow the escape of air are plugged with clay. Finally the funnels at the top and side are capped with clay and the glue is allowed to set for twelve hours THE MUSEUM'S COLLECTION OF LIFE CASTS 29 contour of head and accurate detail of feature. The accuracy of the casts has steadily risen during recent years with the perfecting of methods of technique. Formerly the man who allowed a plaster mold of his head to be taken was subjected to considerable discomfort, which resulted in a cast in which the features were so distorted that it could serve only as a basis from which the sculptor modeled the finished bust; but since the paraffin method has been in use the cast can be gained without distress to the subject, therefore the expression remains true to life and all measurements are accurate. This removal of the necessity of doing any modeling on the casts and therefore of the sculptor's temptation to conventionalize his work has been a most important factor for truth in the ethnological investigations underway. In addition to this largest research value of the Museum's several hundred casts, lesser values are continually realized. Exhibition is of course one of the immediate purposes of the casts. If it is desired to study any given tribe, the exhibition hall shows not only the articles of its culture but also accurate representations of the people themselves. And furthermore, the Museum has continual demand for duplicate casts from universities and colleges and other museums, as well as from artists and various private parties interested in Indian or other primitive types of man. Thus the collection extends its usefulness through sale, exchange and gift. A large number of duplicate casts, to serve for study, exhibition or exchange, can be made from a glue mold A snake group recently put on view in the reptile exhibit of the second floor represents a small part of a South Carolina swamp with its logs and stumps, vines and water hyacinths, the last of interest because often an obstruction to navigation in southern rivers. The group shows side by side poisonous snakes, the water moccasin (Ancistrodon piscivorus) and non-poisonous, the brown water snake (Natrix taxis pilotus). It also exemplifies the viviparous type of snake, the brood of sixty representing the offspring of one of the water snakes. I T would be fortunate if there were some certain rule for distinguishing a poisonous from a non-poisonous snake. That the non-poisonous has large scales on the head is not an infallible guide since the cobras and their allies are quite as innocent looking; that the poisonous has usually a triangular head distinct from the neck is again untrustworthy as many harmless species, like the water snakes, when under the influence of fear, inflate the sides of the head to a semblance of concealed poison glands. Neither does an antagonistic manner tell much because certain harmless forms, like the hog-nosed snakes, so-called "spreading adders ", are aggressive in a higher degree than many deadly species. This lack of distinction is not, for North America at least, the grave misfortune it would seem however, for there has been exaggeration in the popular mind as to the number of poisonous species. In India to be sure, where people go with bare feet and legs through the jungle, the time has been when mortality from snake bite reached twenty thousand annually. This was before the discovery of antivenin, a serum prepared in the same way as germ disease antitoxins and now for sale in India, as in other countries where branches of the Pasteur Institute have been established. As early as 1887 experiments proved that repeated inoculations of snake venom put an animal into a condition resistant to the venom, but not until 1894 was a serum dispensed for practical use. In North America accident from snake bite has always been a rare happening, the dangerous species being few namely, two moccasins, the copperhead and the cottonmouth (Ancistrodon), two coral snakes (Elaps), small brilliantly colored allies of the cobras, and thirteen rattlesnakes (Sistrurus and Crotalus). With the exception of the coral snakes, these are all "pit vipers" and can be recognized when seen near at hand by a peculiar deep depression, of questioned function, between the eye and the nostril and also by a vertical pupil. But for snakes in general the venomous species is marked by no peculiar structure except the poison apparatus. itself, and many non-poisonous snakes even possess the poison glands in a primitive stage of development, lacking only the poison-conducting fang. Therefore in North America where out of about one hundred and ten species only seventeen are dangerous to man, and of these not often more than two occur in a given district, the problem of safety even for extended expeditions into the wilderness demands merely a knowledge of the appearance of the few given forms. Portion of a new snake group that gives acquaintance with the deadly water moccasin of the South [the snake in the foreground; wax cast by James C. Bell, color work by Frederick |