222 



The Cultivation of Anaerobic Organisms 



floats upon the surface of the medium, melts during sterilization, 

 but does not mix with it, and "sets" when cool. The inoculation 

 is to be made while the culture medium is warm, after boiling and 

 before the paraffin sets. 



Koch studied the colonies of anaerobic organisms by cultivating 

 them upon a film of gelatin covered by a thin sheet of sterilized 

 mica, by which the air was excluded. 



Salamonsen has made use of a pipet for making anaerobic cultures. 

 It is made of a glass tube a few miUimeters 

 in diameter, drawn out to a point at each 

 end. The inoculated gelatin or agar-agar 

 is drawn out to a point at each end. The 

 inoculated gelatin or agar-agar is drawn 

 in while hquefied and the ends sealed. 

 The tube, of course, contains no air, and 

 perfect anafirobiosis results. 



Theobald Smith has found the fermen- 

 tation-tube and various modifications of 

 it excellently well adapted to the growth 

 of anaerobes, which, of course, grow only 

 in the closed limb. 



Hens' eggs have been used for anaerobic 

 cultures, and in them the tetanus bacillus 

 grows remarkably well. Conditions of 

 anaerobiosis are, however, not perfect, as 

 can be shown by the behavior of the egg 

 itself. If oxygen be completely shut out 

 by oihng or varnishing the shell, a fertile 

 egg will not develop. 



A quite satisfactory and simple device 

 for routine work with anaerobic organisms 

 has been invented by Wright.* The es- 

 sential feature consists of a pipet, D, with 

 a rubber tube, E, at the end, and one in- 

 terruption connected by a rubber tube, C. 

 The device wiU be made clear at once by 

 a glance at the accompanying illustration. 

 The method of employment is very simple. 

 An ordinary tube of bouillon or other fluid 

 the pipet, the whole being sterilized, the 

 The bouillon being inoculated with the 



62, 63. — Wriglit's 

 method of making anaero- 

 bic cultures in fluid media 

 (Mallory and Wright). 



culture-media receives 



cotton plug in place. 



culture or secretion to be studied is drawn up in the bulb of the 



pipet, A, by suction, until it passes the rubber interruption, C. 



By forcing the upper end of the pipet downward in the test-tube, a 



kink is given each rubber tube and the fluid contained in the bulbous 



part of the pipet becomes hermetically sealed. 



* "Jour. Boston Soc. of Med. Sci.," Jan., 1900. 



