59 



April 23, 1839. 

 William H. Lloyd, Esq., in the Chair. 



A letter was read from Dr. Weissenborn, dated Weimar, Febru- 

 ary 19, 1839. It accompanied a female specimen of the Hamster 

 (Cricetus vulgaris), which he begged to present to the Society, and 

 related to some longitudinal, naked (or nearly naked) marks which 

 are obsei-vable on the hips of that animaL 



These marks. Dr. Weissenborn states, are found in every Ham- 

 ster, though usually hidden by the long fur which surrounds them, 

 and the common opinion of the furriers (who have to cut them out 

 and to repiece the skin) is, that they arise from friction. Being 

 situated over the hip-bones, and therefore more exposed than 

 other parts, the hair is worn whilst the animal is moving in its bur- 

 row. This is the opinion also of the earlier authors, but " is, how- 

 ever, erroneous, as remarked already by Dr. Sulzer, in his valuable 

 monograph on this species, published at Gotha in 1774. These 

 spots are visible the very moment the hair begins to grow, in the 

 naked young, and they are the very places where the growth of the 

 hair becomes first appcirent. At this early stage of the animal's life, 

 they appear on the inner side of the skin, when viewed by trans- 

 mitted or reflected light, as two dark spots. When all the hair is 

 developed the case is reversed, and these spots appear paler than the 

 rest of the skin. Dr. Sulzer confesses himself to be quite ignorant 

 of the part which these peculiar spots act in the CEConomy of the 

 animal, and no subsequent author has explained the subject. I 

 imagine no person, after Sulzer, has turned his attention seriously 

 to it, but it is to be wondered that he was not more successful, being 

 an accurate and clever observer. The reason why the Hamster is 

 furnished with these spots appears to me very far from being myste- 

 rious, and had the cause not been mistaken for the eiFect, I think 

 anybody might have hit upon the idea, that nature had made the 

 short, stiff, and closely adpressed hairs, to grow upon these spots of 

 the Hamster's body, which are most exposed to friction, and at the 

 same time contiguous to bone, that the hair and the skin might be 

 competent to stand the wear and tear to which they necessarily are 

 subjected in the narrow burrow of an animal, which is very brisk 

 in its movements ; and no doubt the skin, which gives rise to a dif- 

 ferent kind of hair, is of a different structure from the rest ; and as 

 this hair is more stiff, the skin which it covers is probably more 

 callous. 



" In the present state of the science of physiology, it may be im- 

 possible to state with sufficient precision the conditions on which the 

 peculiar structure of the skin and hair, in these particular spots, de- 

 pends. The relation in which the latter stand to the hip-bones by 

 peculiar tissues may perhaps help to explain the circumstance, as 



