124 



APPLIED BACTERIOLOGY FOR NURSES 



We know now that these were accidental contaminations. 

 Weigert also described "bodies" included in epithelial 

 cells, which have since been variously interpreted as de- 

 generative forms of tissue cells, or as protozoa causing 

 the disease. 



«^l 



" * ! 



Fig. 39. — Operating-room. Collecting vaccine from a calf. The 

 calves which are used in the preparation of the virus are first 

 washed, the long hair is clipped, and the skin is cleaned with 

 bichlorid solution, then in an alkaline bath, and finally all traces 

 of the antiseptics are removed by thorough rinsing in sterile water, 

 after which the surface to be operated upon is shaved. The ani- 

 mals are then conveyed to the operating-room, where they are 

 vaccinated with tested virus under conditions similar to those ex- 

 isting in the operating-rooms of modern hospitals, after which they 

 are transferred to the propagating stable and kept as clean as is 

 possible. In about six days the virus is removed and prepared for 

 use under rigid aseptic precautions. (Courtesy of H. K. Mulford 

 Company, Phila.) 



Cow-pox is presumably identical with small-pox, 

 being modified because it develops in a different host. 

 When calves are inoculated with small-pox virus they 

 develop lesions very similar to cow-pox. In monkeys 



