CH. VI~\ MICRO-CHEMISTRY 155 



It is very instructive and interesting to examine many organic 

 and inorganic substances with a micro-polarizer. 



REFERENCES TO THE POLARISCOPE AND TO THE USE OF POLARIZED 



LIGHT. 



Anthony & Brackett, 133 ; Behrens ; Behrens, Kossel und Schiefferdecker ; 

 Carnoy, 61 ; Carpenter-Dallinger, 317, 1097; Clark; Daniel, 494; Davis; v. 

 Ebener ; Gamgee ; Halliburton, 36,272 ; Hogg, 133,729 ; Lehmann ; M'Kendrick ; 

 Nageli undSchwendener, 299 ; Quekett ; Suffolk, 125 ; Valentin ; Physical Review, 

 I., p. 127. Daniell, Physics for Medical Students. Nichols, Physics. 



MICRO-CHEMISTRY 



228. During the last decade the microscope has become one of 

 the necessities of the expert chemist, and the signs of the times 

 indicate that in every research laboratory of chemistry the microscope 

 will become as familiar as it now is in research laboratories of biology. 

 Its proper place in chemistry has been admirably stated by Chamot : 



"It is rather remarkable how slow American chemists have been in realizing 

 the importance of the microscope as an adjunct to every chemical laboratory. 

 This is, perhaps, largely due to the fact that few of our students in chemistry 

 become familiar with the construction and manipulation of this instrument, just 

 as few of them become sufficiently familiar with the spectroscope and its manifold 

 uses ; and doubtless also because of the prevailing impression that a microscope 

 is primarily an instrument for the biologist and is of necessity a most expensive 

 luxury. The fact is, however, that this instrument is now far from being a luxury 

 to the chemist, and the time is not far distant when it will be conceded to be as 

 much a necessity in every analytical laboratory as is the balance. 



"Nor is the apprenticeship to its use in chemical work long or intricate. 



"Micro- chemical analysis should appeal to every chemist because of its neat- 

 ness, wonderful delicacy, in which it is not excelled even by the spectroscope, and 

 the expedition with which an analysis can be made. A complete analysis, 

 intricate though it may be, is a matter of a few minutes rather than of a few hours. 



"While there is no good reason to believe, as do some enthusiasts, that this 

 new system is to displace the old analysis in the wet way, every chemist should, 

 nevertheless, familiarize himself with the microscope, its accessories, and the 

 elegant and time-saving methods of micro-analysis, thus enabling him to examine 

 qualitatively the most minute amounts of material with a rapidity and accuracy 

 which is truly marvelous ; not to speak of the many substances for which no 

 other method of identification is known. 



"At present the greatest bar to its general use is the absence of any well 

 denned scheme, and the absolute necessity of being well grounded in general 

 chemistry. There are no tables which can be followed in a mechanical way by 

 the student, but on the contrary he is obliged to exercise his knowledge and judg- 

 ment at every step. For this very reason the introduction of this subject into the 

 list of those now taught is greatly to be desired. ' ' 



