NOVEMBEK 5, 1920] 



SCIENCE 



423 



in which Cohnlieim shone ever brighter and 

 brighter. The particular problem which 

 Cohnheim assigned to Welch was the ascer- 

 taining of the origin of acute general edema 

 of the lungs. This is perhaps not the place 

 to go into minutise of that splendidly con- 

 ceived and executed piece of experimental 

 work. It was in many ways fortimate that 

 Cohnheim was too preoccupied at the time 

 reflecting on his theory of tumors and in 

 the preparation of his text-book on general 

 pathology to do more than propose the prob- 

 lem which Welch develojjed largely accord- 

 ing to his own notions of logical sequence. 

 Cohnheim, indeed, was greatly surprised when, 

 contrary to his preconception of the process, 

 Welch found the factors involved in it to be 

 mechanical. The masterly paper describing 

 this piece of work as it appears in Virchows 

 Archiv was written out by Welch in German 

 and printed quite as he prepared it. Cohn- 

 heim seems not to have altered essentially the 

 composition, the mode of presentation or the 

 conclusions arrived at. Unfortunately for 

 future controversy Cohnheim misconstrued 

 the implications of Welch's experiments and 

 in his epochal Lectures on General Pathology 

 he substituted for the term disprox)ortion 

 {MissverhaUniss) employed by Welch to ex- 

 press the disharmony (often caused by spasm) 

 in action of the two cardiac ventricles, the 

 term paralysis (Ldhmung), which implies only 

 one form of disharmony. 



The by-products of this semester on Welch's 

 development were as important as the direct 

 influences. Salomonsen's studies on tubercu- 

 losis of the eye initiated him into the experi- 

 mental side of the tuberculosis problem. 

 Salomonsen relates an incident showing the 

 great impression made upon the two foreign 

 students by the first example of generalized 

 tuberculosis in the guinea pig which they 

 observed. Their enthusiasm evoked hearty 

 laughter from Cohnheim. It was, moreover, 

 the period of Heidenhain's early brilliant 

 work, of the rich harvest of Colui, the 

 botanist; and to cap the climax, the occasion 

 of Koch's visit to Breslau to lay before Cohn- 

 heim and Cohn the facts of his studies on 



anthrax in the demonstration of which all the 

 workers in Cohnheim's laboratory were per- 

 mitted to share. Finally, Weigert with Ehr- 

 lich was just applying the aniline dyes to the 

 staining of tissue elements and bacteria and 

 had recently completed his study of smallpox, 

 in the course of which he demonstrated by 

 staining methods the masses of micrococci 

 within the pustules. Ehrlich also, although 

 not yet graduated, was literally dabbling in 

 the aniline stains and it was a common event 

 to see him with hands covered up to the wrists 

 with dyes of many colors. The close friend- 

 ship of Welch with Weigert and Ehrlich dates 

 from this period. 



It is significant that the spirit of the Insti- 

 tute was favorable to the new bacteriology 

 and that Cohnheim and his associates were all 

 looking to the new science to unlock doors still 

 concealing the origin of the diseases called 

 infectious — an attitude striking in its differ- 

 ence from the skeptical and rather disdainfid 

 one of the Virchow school of pathology. 

 Thus on leaving Breslau, Cohnheim sent 

 Welch to Vienna by way of Prague, in order 

 that he might visit Klebs, who was engaged 

 in the study of acute endocarditis from the 

 microbiological side. There he spent several 

 stimulating days, during which Klebs showed 

 him through his excellent museum and dem- 

 onstrated his preparations showing micro- 

 organisms (micrococci) in the ulcerative 

 lesions of acute endocarditis. The impression 

 which Klebs made upon Welch was very 

 strong; and in the light of present knowledge, 

 the accuracy and prescience of Klebs' work, 

 well in advance of his period, not only on 

 endocarditis but on diphtheria and experi- 

 mental syphilis as well, have become clearly 

 apparent. 



The next stop in the educational jotmiey 

 was made at Vienna which was still a kind of 

 Mecca for foreign medical students of all 

 nationalities. The immediate objective was a 

 place in Strieker's laboratory, in order to con- 

 tinue his studies in experimental pathology. 

 As an index of the high feelings prevailing at 

 the time it may be mentioned that once 

 Strieker learned that Welch had been with 



