OF THE OX. 75 



Prompted by these principles, which are as 

 logical and fixed as any mathematical deduc- 

 tion, I suggested in 1855 that inoculation 

 should be applied in typhoid fever, which is 

 nothing else but the equivalent of intestinal 

 small-pox, in order to prevent the disease in 

 men. But if the simplest truth sometimes 

 requires a contest of ages before it is heard 

 and understood, I could not hope to fix atten- 

 tion on a fact which might be taken as problem- 

 atical. I felt that I was outrunning time, 

 and that I should neither be heard nor under- 

 stood ; and so it has proved. 



Be that as it may, these typhous diseases 

 have, as is seen, their laws and foreseen de- 

 velopment. They attack animals generally, 

 but chiefly herbivorous animals, endowed, as 

 we have shown in the first part, with a vital 

 resistance which is, relatively speaking, very 

 inconsiderable. 



These febrile typhous diseases (whether their 

 development is caused by a spontaneous mor- 

 bid action in the patient or by an evident 

 contagion), have a period of incubation during 

 which the vital strength undergoes latent 

 morbid modifications, though not sufficient to 



