502 LECTURE XIX. 



constant succession of new-formations from this point, 

 and in the occurrence there is an intus-susception (ab- 

 sorption) of material, by means of which the existing 

 parts enlarge and so the whole tumour grows. On the 

 contrary around the original focus* (Heerd), little new foci 

 are formed, which increasing in size, group themselves 

 around the first, and so gradually give rise to a continually 

 progressing enlargement of the existing tuber.f If the 

 tuber is seated on the surface, we find on section a semicir- 

 cular zone of the most recently formed matter, at its 

 periphery ; if it is in the middle of an organ, the newly 

 apposed foci form a spherical cortex around the older 

 centre. If we examine a tumour after it has existed 

 perhaps a year, it usually turns out that the elements first 

 formed no longer exist in the centre. There we find the 

 elements disintegrating, dissolved by fatty changes. If 

 the tumour is seated on a surface, it often presents in 

 the centre of its most prominent part a navel-shaped 

 depression, and the portions immediately under this 

 display a dense cicatrix which no longer bears the ori- 

 ginal character of the new -formation. These retrograde 

 forms I have described as occurring in cancer, especially 

 in the liver, lungs and intestines, where they are not 

 unfrequently met with, and can readily be demon- 

 strated. 



It is always possible to convince oneself, that, what is 

 called a tumour, constitutes a conglomerate mass, often 

 extraordinarily large, made up of a number of little mili- 

 ary foci (lobules), of which every single one must be 

 referred to a single or a few parent elements. Inas- 

 much as the formations progress in this manner, no 



* Focus here signifies the first rudiment of a tumour, produced by the prolifera- 

 tion of a limited group of cells. See note on Heerd, p. 381. From a MS. Note by 

 tho Author. 



f Tuber = tuberous tumour. See note, p. 4*71. 



