THE CULTURE OF ANAEROBIC BACTEEIA. 309 



method less expensive, they do not materially simplify the 

 procedure. 



Fig. 50 shows an apparatus which was employed at 

 one time by the author. It can be constructed by any one 

 and is simple, inexpensive, and will give excellent results. 

 Ordinary test-tubes are employed instead of the expensive 

 tubes of Liborius. Moreover, a large number of tubes can 

 be placed in one apparatus. The directions for use as 

 given in connection with the author's special apparatus 

 (p. 312), are applicable to this bottle. The stop-cocks 

 serve to seal the apparatus. 



A great variety of apparatus has been described for 

 the purpose of obtaining colonies. Some of these, like 

 Botkin's, enable one to make use of the ordinary Petri 

 dishes. More often, however, they consist of a special 

 dish, such as that of Kitasato. 



Cultures in the presence of air. — This method, from the 

 nature of the organisms under consideration, would seem 

 to be impossible. Nevertheless, as the author has shown, 

 good cultures can be obtained without the use of any spe- 

 cial apparatus, and these cultures are made with appar- 

 ently free access of air. When a tube of glucose agar 

 is liquefied, and then allowed to become solid, a drop or 

 two of water will separate out on the surface. If a stab 

 culture is now made, for instance of symptomatic an- 

 thrax, it will show a good growth not only along the line 

 of inoculation in the deeper layers of the agar, but also 

 in the liquid on the surface. This liquid is apparently 

 in direct contact with the air. It is possible, however, 

 that the carbonic acid and other gases given off by the 

 organism displace the air from the tube, and allow thus 

 a growth to take place. It may be remarked in this con- 

 nection that this growth in the water of condensation is 

 extremely rich in those peculiar spirals known as giant- 

 whips (p. 39). 



