MICROCHEMISTRY. 149 
and may suggest how the microscope serves to test the 
identity and the purity of organic bodies. 
5. The Methods of Systematic Microchemical Analy- 
sis—We have seen that microchemistry is a much 
wider term than crystallography, and covers the study 
of change, of state and of chemical reactions as well as 
crystalline form. In this broad sense, specific micro- 
chemical tests have been suggested by Behrens and 
others for the detection of the elements and the various 
acid radicles. Recently Hinrichs has prepared a com- 
plete outline for qualitative analysis under the microscope. 
Whether such a scheme will ever come into general use is 
doubtful, although it promises results with a minimum 
of time and material; but the study of two typical basic 
and acid groups may prove suggestive to the student. 
A microburner yielding a flame not more than a quarter 
of an inch in height must be provided for melting the 
substances examined, and it is convenient to have the 
lamp so small that it may be placed under the stage of 
the microscope if desired. For ordinary work micro- 
scopic slides are used, a drop of the substance to be tested 
being placed thereon with a fine glass stirring-rod. The 
reagent is added in minute quantity and is made to mix 
with the first by means of a dry stirring-rod. For sub- 
limation tests, two 1-inch watch-glasses are used, one 
inverted over the other, with the substance to be ex- 
amined in the lower, and the appropriate test reagent 
borne on the concave surface of the upper, glass. 
6. The Determination of the Metallic Elements.—Ac- 
cording to the scheme prepared by Hinrichs, solutions of 
