484 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of small cocci, stains by the ordinary dyes, and also by Gram's method ; 

 on gelatin it forms small greyish yellow round colonies, and causes no 

 liquefaction ; it grows slowly on plain agar, the colonies having a deep 

 brown colour ; it grows well on agar with guinea-pig or worm blood. 

 Pure broth culture was inoculated into adult worms by the dorsal vessel, 

 by the mouth, and by the stigmata, and from the results of these experi- 

 ments the authors conclude that the Streptococcus bombycis must be 

 regarded as the specific cause of the disease, which has the nature of a 

 chronic enteritis. The authors think that the lethargy, so often one of 

 the morbid phenomena, should not be considered as a special disease 

 caused by a specific micro-organism, but as a result of a mixed infection. 



Chemical Action of Bacillus lactis aerogenes on Glucose and 

 Mannitol.* — A. Harden and G. S. Walpole, from quantitative examina- 

 tions of the products of the fermentation of glucose and mannitol by 

 Bacillus lactis aerogenes, showed that the ferment action differed from that 

 of Bacillus coli, a proportion of 2 : 3 bivtylene-glycol and acetylmethyl- 

 carbinol, in the first case, being derived from the glucose. The authors 

 point out that the alcohol produced by the Bacillus lactis aerogenes is 

 slightly greater in amount than that produced by Bacillus coli, and that 

 it is at the expense of that part of the molecule which in Bacillus coli 

 fermentation yields acetic acid and lactic acid, that the Bacillus lactis 

 aerogenes forms the new products. 



Resistance of Bacillus coli to Heat.f — St. de M. Gage and G. 

 v. E. Stoughton have made a number of experiments on the resistance 

 of Bacillus coli to heat. They find that in every culture a few of these 

 organisms exhibit an extraordinary resistance, surviving in some cases 

 90° C. for five minutes ; there was no evidence of true spores ; all 

 attempts failed to obtain by subculturing a special highly resistant strain 

 of this organism. The temperature at which final sterilisation occurred 

 varied from 60° C. to 95° C. in 18 different tests ; the thermal death 

 point of the majority of the bacteria was between 50° C. and 55° C. 



The authors consider that the results obtained in the determinations 

 of the normal thermal death point would lead to the belief that its 

 application in the identification of bacterial species would be of more 

 value than the determination of the absolute thermal death point. 



Plasmoptysis of Bacteria.^ — A. Fischer has shown that plasmo- 

 ptysis is an appearance found widely distributed among bacterial cultures. 

 In order to demonstrate this, the organism must be allowed to develop 

 in an unfavourable medium. The comma bacillus of Finkler Prior 

 especially shows this pleomorphism. The medium used by the author 

 was alkaline fleisch-wasser, to which was added 1 p.c. peptone and 1 p.c. 

 cane sugar, and used as broth or with agar ; after a few hours at 32° C, 

 many of the vibrios have taken on oval or spherical forms, all more or 

 less motile ; later, these forms show short outgrowing stalks, often 

 giving the appearance of a Cyclops with its pair of egg-cases, these 

 forms being very numerous by the sixteenth hour ; later, the vibrios are 

 regenerated. Hanging drops of fourteen-hour broth cultures were pre- 



* Proc. Roy. Soc, Series B, lxxvii. (1906) p. 399. 



t Technology Quarterly, xix. (1906) p. 41. 



X Ber. Deutsch. Bot. Gesell., xxiv. (1906) p. 55. 



