1 82 MARSHALL HERTIG. 



their culture in artificial media. Blochmann, their discoverer, 

 was the first to attempt their culture in 1887. He employed a 

 number of common laboratory media, as well as a special cock- 

 roach-infusion medium, but obtained only negative results. 

 A few years later, Krassilschtschik ('89), according to Cholod- 

 kowsky ('91), also attempted the artificial culture of the blattid 

 bacteroids in connection with his work on certain bacteria 

 ("biophytes") found in the bodies of aphids. Though successful 

 in the cultivation of the aphid bacteria, Krassilschtschik failed in 

 his efforts to cultivate the blattid bacteroids. Forbes ('92), in his 

 work on the bacteria normal to the digestive tract of the Hemip- 

 tera, stated that he had been unable to cultivate the bacteria 

 found in the fat-bodies of cockroaches. However, Mercier ('06, 

 '07) announced that he had succeeded in obtaining in pure 

 culture on routine media, the bacteroids of Blatta orientalis. 

 Tubes of bouillon were inoculated with material withdrawn by 

 means of a sterile pipette from the ootheca, one end of which had 

 been sterilized by flaming. In forty such experiments Mercier 

 obtained pure cultures of an aerobic, motile spore-bearer, 

 which he named Bacillus cuenoti. This organism, which grew 

 luxuriantly on all the common laboratory media, resembled 

 closely in cultural characteristics Bacillus subtilis and B. mesen- 

 tericus, organisms commonly occurring as contaminators in 

 cultures. Mercier satisfied himself that Bacillus cuenoti repre- 

 sented the cultural form of the bacteroids and made certain 

 morphological correlations between the bacteroids and Bacillus 

 cuenoti. Mercier obtained cultures from only the single stage, 

 the ootheca, of but one species, Blatta orientalis. Javelly ('14) 

 was unable to confirm Mercier's results. Cultures made by 

 him according to Mercier's technique from a number of oothecse 

 of Blatta orientalis and Blatella germanica remained sterile. 

 Javelly concluded that Bacillus cuenoti was merely contamination, 

 and that the bacteroids had not been cultivated in artificial media. 

 Quite recently Glaser ('20) has reported the artifical culture of 

 the bacteroids of Periplaneta americana and Parcoblatta mrginica. 

 The organisms obtained by him from both species are spirilla 

 growing readily on routine media. These organisms differ in 

 many important respects from Bacillus cuenoti. 



