[ to 



LIQUID CULTIVATING MEDIA. 



Vegetable Infusions. 



57. Watery infusions of hay, turnip, tobacco, &c, which have been 

 largely used in the cultivation of many forms of micro-organisms, are 

 prepared by macerating the several vegetable substances employed 

 in distilled water for eight hours, and then raising the temperature 

 gradually to the boiling point. The infusions are then filtered, 

 transferred to sterile flasks (previously superheated), and sterilised by 

 the method already described under "Animal Infusions " (§ 51, p. 107). 

 They may be made of varying degrees of concentration, according to 

 the requirements of various organisms, and the luxuriance of growth 

 that is wished for. 



Sterile grape juice is obtained by preparing the filtered juice of 

 ripe grapes in the same manner. It affords special facilities for the 

 growth of Torulce and the Mycoderma aceti. 



Artificial Solutions. 



Rauiin's Fluid. 



58. A mineral solution, made up of elements the exact relative 

 proportions of which were determined by the results of chemical 

 analysis of the tissues of the group of micro-fungi (Aspergil/i), for the 

 cultivation of which it was devised. It consists of — 



increase of knowledge as to the intricate chemical relations and food 

 requirements of the group of the moulds. It may be used without 



