420 BOVINE PATHOLOGY. 



of groups of cancer-cells embedded in a fibrous stroma, 

 which is very plentiful. These are of slow development. 



Colloid, gelatinous, adhesive, generally amber yellow 

 and soft, consisting usually of but little stroma and a great 

 number of cells. The cells separate somewhat freely, 

 leaving the areolar network behind. 



Medullary Saecoma or Encephaloid, a lobulated mass 

 of brain-like substance, the skin investing which presents 

 very much enlarged veins, consisting of a more or less 

 plentiful stroma with cells in its loculi. 



It will be seen that each of these forms of cancer con- 

 sists of cells in stroma. The cells are of a special 

 character. They vary very much in form and in their degree 

 of nucleation, but are all endowed with a high degree of 

 vital activity, which seems specially exaggerated in the 

 direction of reproduction. Thus, new cells are rapidly 

 produced within the older ones, and another sign of 

 activity is the tendency to migrate ; softening of the 

 cancer masses leads to ulceration, for the superficial 

 layers of the body become invaded and softened, and thus 

 a large ulcer may be present, the distinctive characteristic 

 of which is the fact that its surface is largely composed 

 of cancer-cells. The discharge is of an ichorous or 

 special character and consists of specific cells ; the danger 

 of cancer lies in this, that it consists of special highly 

 vital tissue, which grows more rapidly than other tissues, 

 and constantly increases in size, involving neighbouring 

 parts ; thus, it extends to the surface and produces an 

 ulcer, which does not tend to heal, and it involves all 

 tissues. Finally, its constituents are conveyed by the 

 lymphatics through the lymph glands, where a similar 

 diseased process results, and thus the blood constantly 

 receives supplies of the specific cells. We must not be 

 understood to imply that there is any special appearance 

 of cancer-cells by which they may be at once determined; 

 their specificity consists in their origin and effects ; they 

 are frequently quite similar to normal tissue elements. 

 The cancerous nature of a tumour may generally be 

 determined by examination of a section of it, or of some 



