June 25, 1897.] 



SCIENCE. 



983 



alkali-peptone bouillon culture about twen- 

 ty-four hours old killed animals weighing 

 from 200 to 300 grammes. This experiment 

 was repeated with the same result, viz., the 

 indol production and pathogenesis were both 

 increased by growth in a medium containing 

 an unusual amount of proteid material so 

 prepared as to be especially suitable for 

 bacterial assimilation. The amount of indol 

 produced by this culture was not greater) 

 however, than is found in other cultures of 

 the colon bacillus which are non-pathogenic. 

 The estimation of the virulence of this or- 

 ganism by the amount of indol formed seems 

 for this reason impracticable. 



Cultures from typJioid spleens. We have 

 found by our experiments that the colon 

 bacillus grown in an excess of proteid ma- 

 terial in an artifical medium iindergoes a 

 disturbance of equilibrium in function, with 

 first an increase of proteolytic activity and 

 later an apparent suppression. Cultures ob- 

 tained from the pathological tissues of man 

 and animals also present characteristics 

 difiering from those of the typical colon 

 bacillus obtained from the healthy colon. 

 For the purpose of demonstrating this modi- 

 fying effect upon cultures of bacteria be- 

 longing to the group under discussion, we 

 have obtained cultures from organs that 

 have been undergoing inflammation for a 

 considerable period of time, viz., typhoid 

 spleens, and have noted their reactions both 

 upon carbohydrate and proteid foods. We 

 have tried to classify these cultures accord- 

 ing to these reactions, and with the follow- 

 ing results : Cultures corresponding to the 

 typical colon bacillus in reaction have not 

 been found among the cultures studied. A 

 group of cultures were obtained which gave 

 one or more of the prominent reactions of 

 the colon bacillus, and appeared to belong 

 to the transitional series of the colon group. 

 A second group gave the characteristic mod- 

 ifications in function that are found in at- 

 tenuated cultures of the colon group. A 



third and larger group gave the reactions of 

 the typhoid bacillus. May not the cultures 

 of the first and second group be colon cul- 

 tures which have been modified in function 

 by growth in an excess of proteid food ? 



Our final test for the differentiation of our 

 cultures obtained from typhoid spleens is 

 the serum test, to which the investigations 

 of Widal have recently drawn so much atten- 

 tion that it has become a well-known and 

 popular diagnostic procedure in tj'phoid 

 fever. We have reversed this test, and 

 have used a specimen of blood which was 

 obtained from a genuine case of typhoid 

 fever, and which had given a characteristic 

 reaction with the typhoid culture used by 

 us for the diagnosis of typhoid fever by the 

 so-called method of Widal for testing our 

 cultures. 



The result of this test showed that only 

 about one-third of our typhoid cultures 

 gave what is regarded by us as a positive 

 reaction, although every culture except one 

 showed a distinct agglutination of the 

 bacilli and some degree of cessation of 

 motility. A comparison of the reactions 

 given by the tj'phoid cultures with those of 

 our cultures from typhoid spleens shows 

 that of 28 cultures derived from tj^phoid 

 spleens, and giving all the cultural reactions 

 of typhoid, bacilli, 18 gave a positive reac- 

 tion, while 10 did not fulfill the require- 

 ments of this reaction in regard to cessa- 

 tion of motion. Two cultures classified as 

 transitional colon cultures gave as typical a 

 reaction as any of the cultures tested. 



Our tests upon the series of typical and 

 atypical colon bacilli show that in one cul- 

 ture of each series a reaction was obtained 

 which seemed as striking as any reaction 

 obtained by us with typhoid cultui-es. 

 Several of the other cultures differed from 

 the control drop by presenting indications 

 of a reaction. 



CONCLUSIONS. 



Assuming the typical colon bacillus and 



