ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 827 



cotton (this may amount to 200 ccm. for each of the large cotton filters 

 employed) are unquestionably objections to this method of filtration, but 

 in its favour it may be stated that one filter, when properly packed, serves 

 to clear a large quantity of medium, and the great saving of time in 

 filtering enables one to prepare a large amount of these nutrients at one 

 operation, which may be stored for future use. Furthermore, the " hot 

 funnel " is disponed with. 



The modifications here described may be best appreciated by the fact 

 that they render it possible to prepare within three hours several litres 

 of the above-mentioned culture media. 



Eggs for Cultivation purposes.* — Dr. F. Hiippe has used eggs in 

 the natural condition for the cultivation of micro-organisms for about 

 twelve months. Fresh eggs are first cleaned and the shell is then 

 sterilized with sublimate solution. They are next washed with sterilized 

 water and wiped with sterilized cotton- wool. This done, an opening is 

 made in the shell with an instrument (previously heat-sterilized) and 

 then the contents are inoculated in the usual way. Before the opening 

 is made the egg is well shaken in order to mix its contents. The 

 opening is closed with a thin piece of sterilized paper, and then the 

 paper coated over with collodion. By this procedure experiments have 

 been made as to the reduction of siilphur compounds to sulphuretted 

 hydrogen and on the cholera bacillus. For the latter purpose the pro- 

 cedure is very favourable, as the conditions resembling those of the 

 intestine with regard to oxygenation are imitated very closely. 



Cultivation on Potato.j — M. Eoux has for more than a year used 

 the following method of cultivating on potato. Without any disinfecting 

 washing the potato is cut up into long slices and these put into test- 

 tubes about 2^ cm. in diameter. About the lower fourth of these tubes 

 is a constriction which prevents the potato slice from slipping to the 

 bottom. The tubes (not hitherto sterilized) are then plugged with cotton 

 wool and heated in a steam sterilizer to 115^ for about 15 minutes. The 

 pieces of potato should be thick enough not to bend. When removed 

 from the sterilizer the surface of the potato is damp, but after being 

 placed in a vertical position in an incubator it dries in a few hours. 

 The potato is then ready for use. The tubes are then covered with a 

 rubber cap and kept till wanted. 



This method, by a simple modification, is applicable to the cultivation 

 of anaerobic micro-organisms. For this purpose a side-piece is added to 

 the test-tube just below the constriction. After inoculation the top of 

 the tube is melted up and then the air is evacuated through the side- 

 piece. Another done, this tube is also melted up. The bacilli of 

 malignant oedema, when cultivated in this way, thrive extremely well. 



Simple Method for reproducing Koch's Cultivation Plates.| — 

 Prof, de Giaxa records a simple method for obtaining copies of the 

 colonies on cultivation plates by a system of coarse photography. After 

 the plate has been removed from the moist chamber, its under surface is 

 wiped with blotting-paper moistened with ether, and it is then placed 

 on a piece of albumen paper which has been sensitized with nitrate of 

 silver. The plate and paper supported by a board are then covered with 



* Centralbl. f. Bacteriol., u. Parasitenk., iv. (1888) pp. 80-1. 



t Ann. Inst. Pasteur, 1888, p. 28 (2 figs.). 



t Centralbl. f. Bakterlol. u. Parasitenk., iii. (1888) pp. 700-2 (1 fig.). 



