412 TUMOURS. 



that they not only enlarge but apparently multiply or propagate 

 themselves ; so that, after one has existed for some time, or has 

 been extirpated, others like it grow, either in widening circles 

 around its seat, or in parts more remote. 



" Mere multiplicity is not a distinctive character of malig- 

 nant diseases, for many innocent tumours may be found in the 

 same person. But in the conditions and circumstances of the 

 multiplicity there are characteristic differences. Thus, when 

 many innocent tumours exist in the same person, they are 

 commonly, or always, all in one tissue. A man may have a 

 liundred fatty tumours, but they shall all be in his subcu- 

 taneous fat. Many fibrous tumours may exist in the same 

 uterus, but it is so rare, that we may call it chance, if one be 

 found in any other part in the same patient ; so many cartila- 

 ginous tumours may be in the bones of the hands and feet, 

 but to these, or to these and the adjacent bones, they are 

 limited. 



" There is no such limitation in the cases of multiplicity of 

 malignant tumours. They tend especially to affect the lym- 

 phatics connected with the part in which they first arise ; but 

 they are not limited to these. The breast, the lymphatics, the 

 skin and muscles, the liver, the lungs may be all, and at once, 

 the seats of tumours. Indeed (and here is the chief contrast), 

 it is more common to find the many malignant tumours scat- 

 tered through several organs or tissues than to find them limited 

 to one. 



" Moreover, if there be a multiplicity of innocent tumours, 

 they have generally a contemporary origin, and all seem to make 

 (at least for a time) a commensurate progress. But the more 

 ordinary course of malignant tumours is, that one first appears, 

 and then, after a clear interval of progress in it, others appear ; 

 and these are followed by others, which, with an accelerating 

 succession, spring up in different parts. 



" Qth. A sixth distinctive character of malignant tumours is 

 that in their multiplication, as well as in their progress of 

 ulceration, there is scarcely a tissue or an organ which they may 

 not invade. . . . 



" Such are the general characters of malignant tumours. 

 Those of innocent ones are their opposite or negatives. Thus 

 innocent tumours have not a structure widely different from that 



