DURATION OF LIFE OF INDIVIDUAL ELEMENTS. 499 



This mode of development, which I have just de- 

 scribed to you, is not, however, in any way peculiar to 

 pus alone, but characterizes every heteroplastic forma- 

 tion ; the first changes which we have shown to take 

 place are found occurring in exactly the same manner in 

 heteroplasms of every sort up to the most extreme and 

 malignant forms. The first development of cancer, of 

 cancroid and of sarcoma exhibits the same stages ; if 



the course of their deve- 

 FlG - 188 - lopment be traced suffi- 



ciently far back, we at last 

 always come across a stage, 

 in which, in the younger 

 and deeper layers, indif- 

 ferent cells are met with, 

 which do not until a later 

 period, according to the 

 particular nature of the 

 irritation to which they are exposed, assume the one or 

 the other type. We may therefore, taking new-forma- 

 tions in general, consider the history of the greater 

 number, and especially of those which principally con- 

 sist of cells, from an entirely similar point of view. 

 The form of ulceration which is presented by cancer in 

 Hs latest stages, bears so great a resemblance to its sup- 

 purative ulceration, that the two things have long since 

 been compared, and quite in the olden time a parallel 



Fig. 138. Development of cancer from connective-tissue in carcinoma of the 

 breast, a. Connective-tissue corpuscles, 6, division of the nuclei, c, division of the 

 cells, d, accumulation of the cells in rows, e, enlargement of the young cells and 

 formation of the groups of cells* (foci Zellenheerde) which fill the alveoli of can- 

 cer,/, further enlargement of the cells and the groups, g. The same developmental 

 process seen in transverse section. 300 diameters. 



* When these groups of cells fall out, the alveoli (loculi) of cancer appear, the 

 relation of the group to the alveolus being the same as that of the bone-cell to the 

 lacuna. From a MS. Note by the Author. 



