PRINCIPLES OF VETERINARY SURGERY 447 ^ 



chicken, five to seven days in the horse, and four to six days 

 in the frog. In the mou.|e, rat and cavy it also varies with 

 the point of entrance; for example, an injection into the 

 brain is followed by a longer period than an injection be- 

 neath the skin. The dose has a little influence on the period 

 of incubation. 



By beginning with a given dose that gives the minimum 

 period of incubation, colossal doses of the toxin can be in- 

 jected, but the duration is not modified. The time interven- 

 ing between the appearance of the first symptoms of tetanus 

 and the death of the animal, however, varies with the dosage. 

 It is therefore evident that the period of incubation is unob- 

 servable. There are neither respiratory nor circulatory dis- 

 turbances, but th^ period is nevertheless noted for organic 

 modifications of a chemical character^ as the following state- 

 ments seem to indicate: Brunner in 1898 proved >hat gas- 

 eous changes are notably active from the very beginning 

 of the period of incubation. D'Arsonval and Charrin in 1898, 

 by placing the same animal in a D'Arsonval calorimeter, 

 proved the existence of a disturbance in the temperature 

 curve ; the dissipation of heat was lessened. 



From these facts it follows that tetanic toxin belongs to 

 a rather peculiar class of toxins. It acts in special thermic 

 conditions and after a period of incubation. The toxin is 

 spread through the organism by degrees, and its ultimate 

 behavior and disposition is interesting. In most infectious 

 diseases the toxins become more and more abundant as fast 

 as the micro-organisms become more and more numerous, 

 and they are found in the liquids and tissues of the patients. 

 But this is not the-case with t-etanic toxin. Hit %ecoiTres"modi- 

 fied in the organism and cannot be found in either the tissues 

 or liquids of the body during the entire course of the disease. 

 Arloing and Tripier have already attempted in vain to repro- 

 duce tetanic spasms by the transfusion of blood from ani- 



