INTRODUCTION 3 



3. The Work of the Micro-analyst in Relationship to that of the 

 Chemist and Bacteriologist 



Just what work should or should not be done by the micro- 

 analyst is as yet not definitely determined; at least, there is no 

 uniformity as to scope of action in the different analytical labora- 

 tories. It is suggested that the following work be assigned to the 

 micro-analyst: 



1. Gross and net weight determination of all such samples as require it. 



2. Moisture determination of substances which require it. 



3. Ash and acid insoluble determinations of substances which are primarily 

 subject to microscopical analysis, as vegetable drugs, pills, powders, vegetable 

 compound powders, etc. 



4. Use of certain special tests, as sublimation tests for benzoic acid, salicylic acid 

 and boric acid; Grahe's cinchona test, wheat gluten test, color reactions for boric 

 acid, capsicum, guaiac, salicylic acid, morphine, etc., tests for cholesterol and phy- 

 tosterol crystals, and others which may prove useful. 



5. Bacteriological testing of foods and drugs generally, of sera, vaccines, galen- 

 icals, syrups, mUk, water, jams, jellies, catsups, etc., as may be required, following 

 the method of the Society of the American Bacteriologists, and limiting the testing 

 to determining the presence or absence of the colon bacillus and other sewage organ- 

 isms, and the usual quantitative bacterial determinations for milk, water and other 

 substances, of which the quality is usually based upon the quantitative bacterial 

 content. 



Substances subject to analysis in the laboratories mentioned 

 should be grouped or classified according to the special or pre- 

 ferred methods of examination to be applied. It is, of course, 

 evident that in the majority of cases chemical as well as micro- 

 scopical methods should be used. In some cases even all three 

 must be used in order that conclusive results may be obtained. 

 The following grouping is suggested: 



1. Substances in which the chemical analysis is of first importance. Chemicals 

 generally, and chemicals in solution, alcohol, alcoholic drinks, flavoring extracts, 

 syrups, oils, fats, etc. 



2. Substances in which the microscopical analysis is of first importance — ■ 

 vegetable substances and preparations which are essentially of vegetable origin. 

 Meats of all kinds, variously prepared, cooked, spiced, etc. 



3. Substances in which the chemical and microscopical examinations are of equal 



