and Laboratory Methods. 1809 



Ifi// (W99) constructed the fermentation tube shown in Fig. 53. It differs 

 from that of Smith in that the open bulb has twice the capacity of the closed 

 branch. This does away with the danger of wetting the plug, when the gas pres- 

 sure in the closed branch forces the liquid into the open bulb. The closed branch 

 is sealed by means of a conical ground glass stopper (S). The stopper is made 

 thimble-shape to avoid the danger of cracking under high temperatures, which 

 might affect a solid stopper. This arrangement enables the experimenter to 

 examine the liquid in the closed branch without disturbing the liquid culture. 

 In addition to these advantages it permits a more ready and thorough cleaning, 

 and simplifies the process of filling. 



G. THE HEN'S EGG AS A CULTURE MEDIUM FOR ANAEROBIC BACTERIA. 



Hiieppe (1891) recommends the following procedure: Use freshly laid eggs. 

 Clean the shell from all foreign matter ; sterilize it by washing it in a solution of 

 sublimate ; rinse in sterile water and dry the shell with sterile cotton. With a 

 flamed instrument make a small opening at the point of the egg. Through this 

 opening inoculate by means of a platinum loop, platinum needle or capillary tube. 

 Then cover the opening with a piece of thin, sterilized paper and seal hermeti- 

 cally by covering the paper with a film of collodion. 



Pearmain's and Moor's Method. — Wash the newly laid egg in a soda solu- 

 tion ; lay it in a ytott solution of bichloride of mercury for a short time ; then 

 rinse the egg thoroughly in water that has been well boiled, finally rinse it in 

 strong alcohol and ether immediately before inoculation. For inoculation pierce 

 the shell with a strong sterile needle and introduce the inoculating material by 

 means of a glass capillary tube, from which it is blown with great care, close the 

 hole with sterile cotton wool. 



Mace (1901) recommends shaking of the fresh egg so that the yolk mixes well 

 with the white. Instead of just washing the egg with sublimate for a short time 

 Mace lets it soak in the sublimate solution for 24 hours. 



VI. 



COMBINED APPLICATION OF TWO OR MORE OF THE ABOVE PRINCIPLES. 



Little need be said with reference to the apparatus that belong to this cate- 

 gory. It is obvious that the large number of methods introduced permits a great 

 variety of combinations that may be successfully used in cultivating anaerobic 

 bacteria. Thus for instance, where it is desired to cultivate bacteria in hydro- 

 gen atmosphere, instead of forcing the air out by the current of hydrogen, the 

 apparatus may first be partly or wholly evacuated by means of a vacuum pump, 

 then it is connected with the Kipp generator. The exhaustion arid filling may 

 be repeated alternately several times. This combination has been used and 

 recommended by Pasteur, Novy and other experimenters. 



Where large apparatus are used, as those of Novy (Fig. 24), Zubinsky (Fig. 

 16), Gabinsky (Fig. 23), etc., a vessel containing a concentrated solution of alka- 

 line pyrogallol may be placed in the apparatus immediately before it is sealed, 



