1911.] Disintegrating Bacterial and other Organic Cells, 65 



Bacteria. 



A direct microscopical count in the case of bacteria is impossible, and the 

 results of grinding were therefore estimated — 



(1) By a general microscopical survey of the specimens, 



(2) By plating and ascertaining the number of surviving micro-organisms. 



I. Cream of Bacillus coli. Amount = 3 c.c. 



(a) Speed 700 revolutions per minute. Besult : a good grind in 

 1 hour. 



(b) Speed 1400 revolutions per minute. Besult : almost complete 

 grind in 1 hr. 



(c) Speed 2400 revolutions per minute. Besult : in \ hour, good 

 grind — nearly as good as in 1 hour at 700 revolutions ; in -| hour almost 

 complete grind. 



II. Cream of B. coli. Amount = 3 c.c. Speed 1700 revolutions per minute. 



Number of living organisms estimated by means of agar plates. 

 Colonies on the Blates. 



Controls before 



After grinding. 



grinding. 



15 minutes. 



30 minutes. 



45 minutes. 



60 minutes. 



1/100,000 dil. 



-1 c.c. 

 405 colonies 



1/100,000 dil. 

 -1 c.c. 

 77 colonies 



1/10,000 dil. 



O'l c.c. 

 138 colonies 



1/10,000 dil. 



-1 c.c. 

 134 colonies 



1/1000 dil. 



-1 c.c. 

 86 colonies 



1/100,000 dil. 



-5 e.c. 

 1978 colonies 



1/100,000 dil. 



0-5 c.c. 

 342 colonies 



1/10,000 dil. 



-5 c.c. 

 678 colonies 



1/10,000 dil. 



"5 c.c. 

 468 colonies 



1/1000 dil. 



-5 c.c. 

 314 colonies 



1/100,000 dil. 



1 -0 c.c. 

 uncountable 



1/100,000 dil. 



1 -0 c.c. 

 576 colonies 



1/10,000 dil. 



1 -0 c.c. 

 1280 colonies 



1/10,000 dil. 



1 -0 c.c. 

 1024 colonies 



1/1000 dil. 



1 -0 c.c. 

 640 colonies 



Average per Unit Volume. 



Control before 

 grinding. 



After grinding. 



15 minutes. 



30 minutes. 



45 minutes. 



60 minutes. 



400,300,000 



67,700,000 I 13,053,000 



11,000,000 



709,300 



With other bacilli, e.g., B. megaterium, B. mycoides, B. subtilis, and 

 B. typhosus, equally good results were obtained. In Blate 1, d is a photo- 



VOL. LXXXIV. — B. F 



