INTRODUCTION 6 



in some of the human diseases, particularly bacillary dysentery and 

 typhoid fever. But here again, always under the domination of a 

 false hypothesis, the studies were made upon intestinal contents of 

 patients in whom the disease was at its height. To this end filtrates 

 were prepared from a suspension of fecal material and these filtrates 

 were combined with suspensions of the bacterium, B. typhosus or 

 B. dysenteriae as the case might be, and these were next inoculated into 

 laboratory animals, hoping thereby to induce symptoms resembUng 

 those seen in the human subject during the disease. At the same time, 

 an agar culture medium was inoculated with the filtrate-bacterial 

 suspension mixture in an attempt to reproduce the cultural "abnor- 

 malities" noted with the coccobacilli from the locusts. 



It is true that this procedure occasionally revealed cultural irregu- 

 larities, but the phenomenon was very inconstant and this fact pre- 

 vented a solution of the question. One day, in reexamining my 

 experimental data my attention was attracted to the fact that when 

 such cultural irregularities appeared it was never at the beginning of 

 the disease but always when filtrates were used which were prepared 

 from fecal material collected during convalescence. I then resolved, 

 and logically this is where I should have commenced, to examine the 

 fecal discharges of individual patients systematically, from the onset 

 of the disease up to the time when convalescence was established. 



In August, 1916, an adult with a severe bacillary dysentery (Shiga) 

 was under treatment in the Pasteur Hospital. Each day about 10 drops 

 of the stool were collected and placed in a tube of bouillon. After incu- 

 bation over night the suspension was filtered through a Chamberland 

 candle. Into some bouillon, previously inoculated with Shiga bacilli, 

 about 10 drops of this filtrate were placed, and the material was re- 

 turned to the incubator at 37°C. 



Throughout the duration of the disease, all of the tubes, prepared 

 each day in the same manner, gave normal cultures of B. dysenteriae. 

 One day, the tube prepared the day before remained sterile. Investiga- 

 tion showed that the patient gave evidence of notable improvement, 

 and, as appeared later, this was shortly followed by definite con- 

 valescence. 



To the bouillon thus inoculated and containing filtrate, and which 

 had remained to all appearances sterile, a suspension of Shiga bacilli 

 derived from a fresh agar culture was added to yield a marked turbidity. 

 This tube was placed in the incubator. After about 10 hours it was 

 again clear. 



r: 



