May 24, 1907] 



SCIENCE 



815 



lated from healthy mouths, and studied in 

 more or less detail. These organisms re- 

 solve themselves in two types: the one a 

 rather short, club-shaped, striated, branch- 

 ing form, and the other a long, filamentous 

 branching form. 



These organisms adhere very tenaciously 

 to the culture media on which they are 

 growing, and this property no doubt mani- 

 fests itself in the oral cavity, where the 

 organisms probably adhere with equal 

 tenacity to the teeth and assist in the for- 

 mation of plaques. They also have the 

 property of breaking up a number of the 

 carbohydrates, and in this way also exert 

 an injurious effect through the formation 

 of acids, thus contributing to caries. 



The study of the pathogenic properties 

 of these organisms is not yet completed. 



The Growth and Toxin Production ty B. 



Diphtheria upon Proteid-free Media: 



Philip B. Hadlet. 



This is the preliminary report of a study 

 whose object was to learn what constituents 

 of proteid-free media were either favor- 

 able or necessary for the formation of toxin 

 by B. diphtherim upon such media. The 

 results thus far attained may be summed 

 up as follows : 



1. Very few cultures of B. diphtherice, 

 fresh from the throats of man, will take up 

 a growth directly upon proteid-free media. 



2. Most cultures which will not at first 

 grow upon proteid-free media may be 

 adapted to grow upon such media. The 

 adaptation may be accomplished by grad- 

 ually diminishing the amounts of bouillon 

 and increasing the amount of proteid-free 

 media in a combined medium consisting of 

 both proteid-free and bouillon until the 

 proteid-free medium itself is reached. 

 Each tube is inoculated from the preceding 

 tube after an incubation of 3-5 days. 



3. "Whether the growth of B. diphtherice 

 upon proteid-free media be spontaneous or 



the result of adaptation, there may be 

 formed a toxin as virulent as that obtained 

 from bouillon cultures. 



4. Of the three nitrogen bases tried (as- 

 para^in, urea and glycocoll), ui'ea seemed 

 to be of little value, while glycocoll fur- 

 nished the best growth and strongest toxin. 

 Asparagin appeared to give better results 

 than urea, though it was not as satisfactory 

 as glycocoll. 



5. A single morphological variety of B. 

 diphtherice may be decidedly modifiable; 

 and there are facts which point to the 

 view that there may be, in the life of the 

 diphtherial organism, what we may roughly 

 call a cycle of adaptive forms, each one of 

 which is best suited to a circumscribed 

 condition of environment in which it may 

 or may not produce a virulent toxin. 



6. In all cases of growth upon proteid- 

 free media, whether spontaneous or result- 

 ing from adaptation, it is the solid-staining 

 varieties of the diphtherial organism which 

 manifest the most luxuriant growth. 



On the Cultivation of Spirillum Oher- 

 meieri: F. G. Novy and E. R. Knapp, 

 the Hygienic Laboratory, University of 

 Michigan, Ann Arbor, Mich. 

 The Spirillum Oiermeieri has been main- 

 tained in this laboratory, since November, 

 1905, by a consecutive passage through rats. 

 Although during this time many hundreds 

 of attempts to secure cultures on artificial 

 media have been made they have given uni- 

 formly negative results. In the defibri- 

 nated blood of infected rats, the spirilla re- 

 tain their vitality for a variable length of 

 time depending upon the stage of the dis- 

 ease during which the blood is drawn. If 

 drawn during the decline stage, that is to 

 say at a time when the organisms have 

 reached their maximum and are beginning 

 to decrease in numbers, the spirilla wiU 

 often die out in*less than 24 hours. This 

 is due, as we have shown, to the presence of 



