654 RUDOLPH VIRCHOW, 1821-1902. 



that the life processes Jo not reside in the cell as a whole, but are 

 proper to certain smaller parts, the nature of whose activity deter- 

 mines disease or health, but these views have not been maintained. 

 Biolog-}' is cellular, and medical thought remains cellular in its pathology. 



We have hitherto been tracing- the course of Virchow's life and 

 noting the principal achievements, which stand like milestones to mark 

 his advance. Continuing in this wa}', we nmst now take note of one 

 of his greatest works, namel_y, "Die krankhaften Geschwiilste."" It is, 

 to be sure, incomplete, for only 25 of the proposed 30 lectures composing 

 it appeared in the two and a half volumes published. But what Virchow 

 has set down in these three books remains to-da^^, after almost forty 

 years, an indispensable reference work and a guide to those working 

 in this subject. The exempli tication of the scientific i:>rinciple of pro- 

 ceeding to the understanding of a thing from an investigation of its 

 development, the deep thorough discussion of a wealth of confirmed 

 experimental material, all this coml)ined with the Ijrilliant presentation, 

 have caused the " Oukologie " to take rank as the greatest of Virchow's 

 works. 



Just as he chose the genetic method in seeking the explanation of 

 the significance of all discoveries by an inquiry into the nature of their 

 origin, so also Virchow did not neglect to employ the same method to 

 investigate the causes of phenomena. He studied the a?tiology of 

 diseases in the widest sense, and his investigations of the parasitic 

 diseases, the causation of affections b}^ the action of animal or vege- 

 taljle parasites within the tissues, formed a considerable part of his 

 etiological researches. It is not possible to enter upon them within 

 the limits of this article, but in the interest of truth it should be stated 

 that at no time in his life did Virchow mistake the importance of 

 plant forms of disease germs, and never opposed any movements of 

 thought leading in this direction. Thus, in 1858, we find in the Archiv ^ 

 "Beitrage zur Lehre von den l)ei Menschen vorkonmienden ptlanz- 

 lichen Parasiten.'' He gives here, among other observations, the first 

 good description of fungus diseases of the lungs and bronchial tubes 

 {Broncho- an (LPneuinotioni yl'osls aspergilllna and Pn. Harcinica). 



His theories furnished the ground work for the later rise of l)acteri- 

 ology. It was supposed by many that there was an outspoken oppo- 

 sition, or at least a distrust, on Virchow's part of the revolution in 

 bacteriological methods which was going on under the leadership of 

 Robei't Koch. Nothing could l)e more incorrect. Virchow, who had 

 himself done much in the interest of a scientific explanation of the 

 many facts which lie had brought to light, had pointed out the direc- 

 tion which this ])i-anch of general patholog}'^ was to take, and gladly 

 recognized all contributions to the science. It was onl}^ against the 



"I'.crliii, lSt;;5-lS(i7. ''Arcliiv, vol. 9, pp. 557-593. 



