GENERAL SYSTEMATIC BACTERIOLOGY 339 



l^vogyre." It differs from the genus Aerobacter in that no hydrogen is 

 produced. Included in this genus are those forms which produce lactic 

 acid at temperatures above 30°C. and which are responsible for the 

 fermentations of Kefyr, of Koumys and of the IMatzoon. The acidi- 

 fication begun by the Lactococcus is continued in milk by Lactobacillus. 

 These organisms are likewise responsible for the souring of ensilage, 

 and constitute the socalled acidophOe flora of the intestines of infants. 

 The species Lactobacillus fermentum, L. delbriickii and L. caucasicus 

 are listed, the two former from fermentation industries, the latter from 

 Kephir. 



Beijerinck saj'-s (1901, p. 213) that Lactobacillus and Lactococcus 

 "sont certainement des genres phylogenetiques et nur point des 'genres 

 physiologiques' comme par exemple Photobacter, ou simplement mor- 

 phologiques comme les 'genres' Bacillus, Pseudomonas, Micrococcus, 

 etc." Later he diagnoses the genus as follows: 



Au genre Lactobacillus doirent etre rapportes les ferments lactiques actif de 

 forme bacillaire qui produisant I'acide actif levogyre et qui se rapprochent du 

 genre Aerobacter dont jai donne la diagnose en 1900. Pourtant Lactobacillus se 

 distingue de se genre en ce que la production I'hydrogene, caractere important 

 pour le diagnostic d' Aerobacter y manque absolument, ainsi que dans tous le autres 

 ferments lactiques actif s. 



Beijerinck (1908, p. 370) discussed the characters which differentiate 

 Lactobacillus caucasicus and L. longus. 



The type species is somewhat difficult to determine. Beijerinck 

 (1901) states that the question of species is troublesome, then 



Passant sous silence pour le moment les L. fermentum et L. Delbrucki, pro- 

 ducteurs du levain lactique, nous rencontrous en premier lieu le Lactobacillus 

 caucasicus, dont les zooglees sont bien connues sous le nom de grains de Kefyr. 



He then describes the last named species. It would seem that al- 

 though L. fermentum is first mentioned, L. caucasicus may be regarded 

 as the type. 



Winslow et al. (Committee Soc. Am. Bact. 1917, p. 561) state the 

 generic characters are those of the family Lactobacillaceae and the 

 type species is L. caucasicus (Kern?) Beijerinck. 



Buchanan (1918, p. 54) states: 



Rod-shaped organisms, cells frequently quite elongate, non-motile, without 

 spores, Gram-positive in young cultures. Produce acid, largely lactic, from 

 carbohydrates. When gas is produced, it is CO2 without hydrogen. For the most 

 part the organisms are thermophilic. Microaerophilic. 



The type species is Lactobacillus caucasicus (Kern) Beijerinck. 



