70 THE CELL DOCTRINE. 



velopment of these that tubercle and cancer arise 

 (Fig. 15), and similarly all pathological new forma- 

 tions. N'one of these products are exudations from 





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 iill the alveoli of 

 cancer. /, Further enlargement of cells and groups, g, The same development 

 seen in transverse section. (From Virchow.) 



the blood, according to Virchow. They are entirely 

 local in their origin. In these views he is supported 

 by the majority of German observers. 



Another mode of formation of pus is however ad- 

 mitted by Virchow, in the growth and development 

 of new cells in epithelium, whether in cuticle or mu- 

 cous membranes. Whether forms of suppuration 

 exist which may be referred to muscular, nervous, 

 and capillary elements, he considers doubtful. 

 -' A fourth and final distinctive feature of Virchow's 

 views, concerning which there is less unanimity, even 

 among German histologists, is his peculiar system of 

 canals or tubes, produced by the anastomosis of one 



