MICROSCOPICAL DIAGNOSIS. 79 



are easily and rapidly disseminated. While in the former the can- 

 cers the blood-vessels course within the stroma and very rarely in- 

 deed do they communicate with the alveoli. Thus, it is very rare, if 

 ever, that the cancers are disseminated by means of the blood-cur- 

 rents. However a study of the lymphatics shows them to be numer- 

 ous, accompanying the blood-vessels and communicating freely with 

 the alveolar spaces. The elements thus enter the lymphatics readily 

 and are carried to the nearest glands where they are caught in its 

 meshes and are carried further on, not, however, until the gland it- 

 self has become sufficiently affected to furnish other elements. In 

 the cancers, then, dissemination is slow and accomplished through 

 the lymphatics. All cancers are very liable to undergo fatty meta- 

 morphosis, especially the young and rapidly growing varieties. 



Fig. 28. Cells from Stir r hits, 



Scirrhus or chronic cancer, as its name implies, is of slow growth 

 and of a firm and hard structure. In this variety the alveoli are 

 small and comparatively poor in cells. Instead of the organs affect- 

 ed being increased in size they are many times actually reduced, of- 

 ten depressed in the centre and firmly attached to the skin. A mi- 

 croscopical examination of the centre of this growth may reveal 

 nothing but cicatricial tissue. The cells have suffered degeneration, 

 while the stroma has atrophied and contracted. At the periphery 

 will be found a zone of cells, and free nuclei infiltrating the neigh- 

 boring tissues. Between the two will be seen the characteristic alveo- 

 lar stroma together with the cells. Its most frequent seat is in the 

 female mammae and in the stomach. The secondary growths arising 

 from it are generally encephaloid. 



Encephaloid or acute cancer differs from the above mostly in 

 its rapid growth and small amount of stroma. It is usually very soft 

 and by scraping the fresh cut surface an abundance of' juice is given 

 off, rich in cells, free nuclei, granular matter, etc. 



