ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 



1037 



Fig. 181. 



^ 



be re-filtered. In order that the mass may have the proper degree of 

 consistence it is necessary to use only 350 c.cm. of water in making the 

 meat infusion instead of 500, in view of the addition of the 150 ccm. 

 wine. 



All kinds of microbes thrive excellently on this medium. 



Albumen of Plovers' Eggs as Nutrient Medium for Micro- 

 organisms.* — Dr. D. Dal Pozzo prepares the albumen of plovers' eggs 

 in the following way. The egg is first carefully cleaned externally, 

 and then, having been opened, the thin albumen which runs out is 

 received into a sterilized vessel. To this one-fourth of water is added, 

 and then the medium is poured into test-tubes, &c., where it is discon- 

 tinuously sterilized, and allowed to set obliquely. From one egg four or 

 five tubes may be filled. If necessary the medium may be modified with 

 glycerin, dextrin, paste, &c. The thicker portion of the albumen sur- 

 rounding the yolk may also be made use of by diluting it with water, 

 and even with glycerin ; it is then filtered and treated as 

 before. Discontinuous sterilization is not absolutely neces- 

 sary, as the albumen is always free from micro-organisms. 



The albumen mass may also be used for the production 

 of plates. The inoculating matter is finely disseminated 

 throughout the albumen, and the plate is then dried over 

 sulphuric acid, and the micro-organisms developed in a moist 

 chamber at ordinary temperatures. 



New Method for Cultivating Anaerobic Micro-organ- 

 isms-t — Dr. H. Buchner's method consists in absorbing the 

 oxygen by means of pyrogallio acid. There results an 

 atmosphere of nitrogen and a little carbonic acid mixed 

 with a trace of carbonic oxide. 



The apparatus is shown on a reduced scale in fig. 181. 

 The outer tube is usually made 22-24 cm. long and 3 cm. 

 wide, the inner tube having corresponding proportions. In 

 the bottom of the outer tube is placed 1 grm. of dry com- 

 mercial pyrogallic acid, and on this by means of a pipette 

 are poured 10 ccm. of a 10 per cent, solution of caustic 

 potash. The smaller tube containing the previously inocu- 

 lated gelatin, &c., is then placed within the larger one, and 

 prevented from reaching the bottom by means of a wire 

 stand. The smaller tube is plugged with cotton wool, and 

 the outer one with a caoutchouc bung. 



If the air space in the outer tube amount to 100 ccm., the 

 quantity of pyrogallic acid to 1 grm., and that of the potash 

 solution to 10 ccm., then the absorption of oxygen is com- 

 pleted in an incubator at a temperature of 37° in 24 hours. 

 If the temperature be only 20° C, then it takes about two 

 days to remove the oxygen entirely, while at 0° C. the absorption is very 

 slow. 



Frequent shaking of the pyrogallic acid produces of course a quicker 

 absorption, and the addition of the alkali boiling hot accelerates the 

 action. This method is said to save much time and labour in the 

 laboratory. 



* Med. Jahrb., 1887, pp. 523-9. 



t Centralbl. f. Bakteriol. u. Parasitenk., iv. (1888) pp. 149-51 (1 fig) 

 1888. 4 A 



.Ml 



