UPON CATTLE PLAGUE REPORT. 243 



not think any one will urge as an objection to the 

 general application of the doctrine here taught that 

 these same characters ought to have been proved in 

 the case of every contagious malady known to us. 

 As well might it be argued that we cannot accept any 

 conclusions as to the nature of pus until the pus 

 produced under all possible kinds of pus formation, 

 and in every part of the organism has been submitted 

 to investigation. Knowing what we do of the several 

 diseases, it would not be reasonable to infer that the 

 poison of small-pox consisted of matters in an essentially 

 different state from that of vaccine poison, or that the 

 poison of typhus, typhoid, relapsing fever, scarlet 

 fever, and measles, consisted of matter in very different 

 physical states, in one fever being a gas, in another a 

 liquid, in one an alkaloid, in another a protein sub- 

 stance, and so on. Such a doctrine would be abso- 

 lutely untenable. It may, however, be urged by 

 dissentients, that the evidence I have adduced in 

 favour of the contagium of all contagious fevers being 

 a form of bioplasm, is not conclusive, because every 

 individual contagious fever has not been subjected to 

 precisely the same course of minute investigation. 



The minute contagious bioplast is less than the 

 TTTolooTJ'th f an mc h m diameter, and often so very 

 clear and structureless as to be scarcely distinguishable 

 from the fluid in which it is suspended. Such a 

 minute particle may readily be transferred from the 

 affected organism to an apparently sound organism. 



