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Vol. VIII. DETROIT, MARCH, 1888. No. 3 



ORIGINAL COMMUNICATIONS. 



THE SPECTROSCOPE AND ITS APPLICATION TO MEDI- 

 CAL PRACTICE.* 



DR. S. WATERMAN. 



[Continued.] 



DELICACY OF THE SPECTRUM TEST. 



^ I HE delicacy of the spectnim test is extraordinary, and sur- 

 -*- passes in this direction any other test previously known 

 to the analytical chemist. 



Let me quote here the statement of Dr. H. Schellen. In his 

 excellent work, " Die Spectralanalyse," he says: "Suppose we 

 divide one pound of our common table salt (sodium chloride), into 

 500,000 equal parts. One of these parts, or minute particle, we call 

 a milligramme. In order to weigh out such a milligramme it is 

 necessary to employ the most delicately constructed scales; the 

 weigher himself must possess a high degree of dexterity, and he 

 must proceed with the greatest possible care. But with this 

 performance he has pretty nearly arrived at the limit of possibilities. 

 But what if we should require of him to take one of these milli- 

 grammes, and to divide it again into 3,000,000 equal parts ? Could 

 he perform this feat? Certainly not. The human mind cannot 

 conceive the minuteness of such an atom of matter. The spectro- 

 scope, however, does not recoil from such a supernatural task. It 

 demonstrates the presence of such an inconceivable atom with the 

 utmost precision and certainty. The dusting of a book in the 



♦Copyright, 1888. 



