MICROSCOPICAL DIAGNOSIS. 77 



cells. This variety increases with a rapid growth by invading the 

 healthy surrounding structures, involving the lymphatics and inter- 

 nal organs. It is full of blood-vessels easily ruptured. It is not to 

 be mistaken for encephaloid cancer, which it resembles by physical 

 characters. Here the cells are of a nearly uniform size and char- 

 acter, and there is an entire absence of an alveolar stroma. When 

 an alveolar stroma is present careful attention must be given to no- 

 tice whether the cells are grouped together in these alveolar spaces 

 or exist singly and alone. If the latter then it is termed an alveo- 

 lar sarcoma, if the former, it belongs to one of the cancers. It is 

 often very difficult to distinguish between the two. A myeloid sar- 

 coma is usually found growing in connection with bone, especially 

 from the medullary cavity. The nuclei vary in number from two or 

 five to ten or fifty. These large cells are generally separated from 

 each other by a number of cells of the spindle-shaped variety, 

 among which are seen a few round or oval ones. It is quite fre- 

 quently encapsuled, most frequent in early life, and is the least 

 malignant of all the sarcomata. 



Thus it will be seen that all the sarcomata possess malignant 

 properties, in this respect ranking next the cancers. They dissemi- 

 nate by means of the blood-vessels, and thus rarely infect the lym- 

 phatics, a clinical distinction between these growths and the can- 

 cers, marked and distinct. For this reason they are reproduced 

 with greater rapidity than the cancers. The lungs are the most 

 favorite seat for the secondary growths. No one variety of the sar- 

 comata is necessarily malignant, while again the same variety may 

 recur in the same place many times. 



THE CARCINOMATA. 



A cancer is a growth consisting of a fibrous, alveolar stroma, 

 the meshes of which are filled with cells of an epithelial type. 

 While the cells have no "specific" character, yet they are recog- 

 nized by their large size, irregular shape, the prominence, number 

 and size of their nuclei and nucleoli. These cells exhibit every pos- 

 sible shape. They are full of granular matter, and from their great 

 liability to undergo fatty degeneration they usually contain some fat 

 globules. In the juice of the cancers will be found numerous free 

 nuclei, especially in the younger and softer growths. Cells not very 

 unlike these are found in the normal tissues or in those tissues when 



