434 PRINCIPLES OF VETERINARY SURGERY 



incapable of germinating when they enter the sound tissue 

 of an animal in good health and in a state of purity. This 

 is due to the fact that when they are introduced under the 

 skin or into the peritoneum they are surrounded, immobil- 

 ized and destroyed by the polynuclear leucocytes. This 

 prophylactic role of the leucocytes is established by exam- 

 ination of the part afifected. After inoculation of a heated 

 culture there is a thickening of the connective tissue — a no- 

 dosity due to the influx of the polynuclear leucocytes. By 

 excising the tumefaction and examining the contents, it 

 is easy, by staining with fuscin or methylene blue, to follow 

 the fate of the spores and to understand their relationship 

 with the cellular elements. It is proved that leucocytes 

 abound at infected points. At the end of twenty-four hours 

 there were thirty leucocytes to every spore. Gradually the 

 exudate becomes richer in leucocytes as the free spores di- 

 minish, and at the end of two or three days all are incor- 

 porated. It is established that they diminish little by little, 

 undergo degeneration and after five or six days are des- 

 troyed. 



But whether the resistance of the germs varies, or wheth- 

 er the cells are not always equally capable of destroying 

 them, some spores may remain intact and virulent in the 

 cellular protoplasm for three months or more. This view is 

 important in explaining the origin of cases of tetanus whose 

 cause remains obscure. 



There is a direct relation between phagocytosis and the 

 preservation of the animal. All the influences that lessen 

 or hinder the work of the leucocytes likewise permit the 

 growth of the spores and thus favor the development of 

 the disease, and substances having negative chemiotactic 

 properties, added to spores deprived of toxins, favor the de- 

 velopment of fatal generalized tetanus. The rabbit which 

 resists an injection of 55 to 65 cubic centimeters of the cu.l- 



