254 LECTURE X. 



to render it probable that the transferrence takes place by 

 means of certain fluids, and that these possess the power 

 of producing an infection which disposes different parts 

 to a reproduction of a mass of the same nature as the 

 one which originally existed. We need only imagine a 

 process similar to that which we see upon a large scale 

 in small pox. The pus of small pox when directly ino- 

 culated does indeed induce the disease, but the conta- 

 gium* is also volatile, and a person may have pustules 

 over his skin after merely breathing air of a certain cha- 

 racter. A similar state of things seems to prevail in 

 cases, in which, in the course of heteroplastic processes, 

 dyscrasise occur which do not burst out afresh at points 

 which, according to the direction of the current of blood 

 or lymph, would be most directly exposed to them, but 

 at remote spots. As the salts of silver do not deposit 

 themselves in the lungs, but pass through them to be 

 precipitated only when they reach the kidneys or the 

 skin, so an ichorous juice may pass from a cancerous 

 tumour through the lungs without producing any change 

 in them, and yet at a more remote point, as for example 

 in the bones of a far distant part, excite changes of a 

 malignant nature. 



* i. e. Contagious matter. Transl. 



