456 HILDA HEMPL HELLEE 



I, Agar colonies — von Hibler and older workers used also gelatin. 



A. Surface colonies. 



1. On plates. 



2. On tube slants. 



B. Deep colonies. 



1. In Petri dishes. 



2. In deep agar tubes. 

 II. Colonies in liquid media. 



A. Isolation of a single bacillus by the India-ink method. 



B. Isolation of a single bacillus or of a smaU number of organisms 



by the technique of Barber. 



C. Isolation of a single baciUus by the technique of Schouten, 



of Hecker, of Holker, or that of Malone. 



Isolation from surface colonies has been emploj'ed by many work- 

 ers with anaerobes. VeiUon and Zuber list a large number of 

 tjT)es of anaerobic apparatus, von Hibler (1908) gives a bibli- 

 ography of various plates and apparatus for purposes of anaerobic 

 culture, Besson's textbook figures a number of arrangements, and 

 Fildes describes various methods at the end of 2vIcIntosh's report. 



Henry uses plates of agar which he streaks with egg-albumen 

 and incubates in hydrogen. Stoddard uses slants made of the 

 modified egg medium of Stitt, made with tryptic broth and 1 per 

 cent glucose. Zeissler, who at first used glucose agar plates con- 

 taining human blood for the isolation of anaerobes, later employed 

 horse blood and sheep blood agar plates. ]Many laboratories now 

 make use of large slants of blood agar, kept under anaerobic con- 

 ditions for the isolation of anaerobes. Isolation of nitrogen fix- 

 ing organisms was accomplished by Winogradsky by inoculating 

 cultures on pieces of carrot which he placed in vacuo, and Fribes 

 isolated pectin fermenters on potato slants rubbed with chalk. 

 ^Mcintosh prefers agar slants to plates for isolation procedure. 

 He reiterates: ''It cannot here be impressed too strongly on the 

 worker that the purity of a culture can only be tested and con- 

 trolled by repeated surface cultivation," and he speaks of the 

 Veillon-tube method of continental workers as giving impure 

 cultures. I have used plating occasionally and am familiar with 

 technique necessary^ to make anaerobes grow on plates. In fact 



