638 



APPENDICES. 



following purposes : — One is used to contain distilled water, with 

 the nozzle hanging down conveniently within reach of the working 

 table; the other is to contain a solution of carbolic acid (1 in 20), 

 and may be placed so that the nozzle hangs close to the lavatory 

 sink or basin. The former replaces the use of the ordinary wash- 

 bottle, in washing off surplus stain from cover-glasses, etc., and the 

 latter is conveniently placed for disinfection of vessels and hands 

 after cleansing with water. They should be placed on the top of a 

 cupboard or on a high shelf. 



Desiccator. — The desiccator (Fig. 273) consists of a porcelain 



pan containing concentrated 

 sulphuric acid and covered 

 over with a bell-glass receiver. 

 The sheet of plate-glass upon 

 which the pan rests is ground 

 upon its upper surface, and 

 the rim of the glass bell is 

 also ground and well greased. 

 In the centre of the pan is a 

 column supporting a circular 

 frame, which is covered with 

 wire gauze. Slices of potatoes, 

 upon which micro-organisms 

 have been cultivated, are 

 rapidly dried by the action of 

 sulphuric acid in confined air. 

 A detailed description of other kinds of apparatus commonly in 

 use in a research laboratory — such as the various forms of apparatus 

 for filtering cultures in liquids, and the reagents necessary for 

 special chemical investigations — must be sought for elsewhere. 

 Much information may be obtained about the most recent improve- 

 ments in bacteriological, chemical and physical apparatus by 

 reference to manufacturers' catalogues.* 



* All bacteriological apparatus may be obtained frora Berlin from Dr. 

 Muencke, 58, Louisen Strasse, or Dr. Hermann Rohrbeok, 24, Karlstrasse. 

 Dr. George Griibler, Leipzig, is recommended for special staining reagents. 

 In London, chemicals and bacteriological apparatus can be obtained from 

 Becker & Co., Hatton Wall, or from Baird & Tatlock, 14, Cross Street, Hatton 

 Garden, E.C. Mr. Baker, of High Holborn, W.C., is recommended as the 

 agent for microscopes and objectives by Continental makers, including 

 Zeiss' apochromatic objectives. 



Fig. 273. — Desiccatoe. 



