370 



SCIENCE. 



[N. S. Vol. XV. No. 375. 



tion, 1 to 49 (or 1 to 499 if the species are 

 numbered in the thousands). Thus: 

 B. mallei from one liorse=401, 

 B. mallei from a second liorse=402, 

 B. mallei from a different lesion in the second 

 liorse=403. 



The first culture isolated pure is given 

 a number in the first place of decimals— 

 thus the pure culture of glanders bacilli 

 from the first horse mentioned would be 

 401.1. 



Subcultures are expressed by the num- 

 ber of the original culture with the figure 

 1 placed in the next right place of deci- 

 mals. If further subcultures (sister cul- 

 tures) are made from the same mother cul- 

 ture, they are differentiated by increasing 

 this last new figure in arithmetical order. 

 The system is very simple, very accurate, 

 very elastic, and, construed under the card 

 catalogues described, saves an enormous 

 amount of work, and ensures a complete 

 record of every tube used. 



Variety of the Hog Cholera Bacilhis ivhicli 

 closely resembles Bacillus typhosus: 

 M. Dorset, Biochemic Laboratory, 

 Washington, D. C. (By title.) 

 The author described a variety of the 

 hog cholera bacillus which was isolated 

 from a virulent outbreak of hog cholera in 

 Page County, Iowa. This variety corre- 

 sponds in every way with the hog cholera 

 bacillus as usually seen, except in its ac- 

 tion upon glucose, which it ferments with- 

 out the evolution of gas. The failure to 

 produce a gaseous fermentation of glucose 

 places this variety of the hog cholera bacil- 

 lus culturally closer to Bacillus typhosus 

 than to the hog cholera group of bacteria. 

 A comparison with several cultures of Ba- 

 cillus typhosus has shown that culturally 

 this variety of hog cholera bacillus cannot 

 be distinguished from some of them ; but 

 the author concludes that when the source 

 and pathogenic properties of this variety 



are considered, it should be classed among 

 the hog cholera bacteria. 



The Morphology of Bacillus Diphtherice: 



Frederic P. Gorham, Brown University, 



Providence, R. I. 



The experiments described were made 

 for the purpose of proving that the long, 

 granular form of the diphtheria bacillus, 

 type C of Westbrook, can be changed into 

 the short, thick, solid-staining, sometimes 

 double-headed bacillus, type D^ of West- 

 brook. A pure culture of type C was made 

 from a clinical case of diphtheria. After 

 several platings a culture Avas obtained that 

 showed only long granular forms, careful 

 search and the use of Neisser's stain fail- 

 ing to demonstrate a single bacillus of any 

 other type. Plates were made from this 

 culture and some thirteen colonies exam- 

 ined. The colony that showed the largest 

 number of shorter forms was selected, and 

 plates made from it. This process of selec- 

 tion and plating was continued for some 

 fifteen generations. 



The colony of the fourth generation was 

 composed of forms distinctly smaller than 

 those of the original culture; all were still 

 granular, however, and stained by Neisser 's 

 method. In the fifth generation, some of 

 the bacilli failed to show granules by 

 Neisser's method, were barred, and of the 

 type C of Westbrook 's. In the eighth gen- 

 eration many of the bacilli failed to react 

 to Neisser's stain, and a large number of 

 barred and solid staining forms were pres- 

 ent. Some of these approached the double- 

 headed type D^. On continuing the selec- 

 tion until the fifteenth generation all the 

 granular forms were eliminated and the 

 colony became a pure culture of the type 

 D^ ; the majority of forms were of the 

 double-headed variety. 



The experiment is being continued by 

 testing the various types for virulence. 

 From the results already obtained it ap- 



