OLIVER WOLCOTT GIBBS 115 



undertook in 1889 with H. A. Hare and later with E. T. 

 Reichert the systematic study of the action of definitely re- 

 lated organic compounds upon animals. His ideal was the 

 establishment of principles whereby the physiological effect 

 of drugs might be enhanced or modified step by step, so as to 

 produce gradations of physiological effect comparable to the 

 shading of the spectral colors. The experimental work was 

 done by his associates, and did not progress far enough to 

 lead to definite conclusions upon this idea. 



The name of Gibbs will, however, be chiefly associated 

 with his three great researches on the cobalt-ammines, the 

 platinum metals and the complex acids. The oxidation of 

 cobalt in ammoniacal solutions had been observed by Gmelin 

 as early as 1822; but F. A. Genth first produced well-defined 

 salts of an ammonia-cobalt base in 1847, publishing his results 

 in 1851, in which latter year papers were published in France 

 by Claudet and by Fremy, who defined four distinct series. 

 Gibbs discovered xanthocobalt in 1852, and thereupon asso- 

 ciated himself with Professor Genth, then at the University 

 of Pennsylvania, in a thoroughly systematic study, to which 

 Gibbs seems to have contributed the greater portion of the 

 experimental detail. The results were published by the 

 Smithsonian Institution in December, 1856; but the second 

 series of the work was presented by Gibbs alone to the Ameri- 

 can Academy of Arts and Sciences in 1874 and 1875. These 

 papers are noteworthy for the thoroughness with which 

 each of the many series was studied, analytically as well as 

 synthetically; he not only showed that the same type of 

 cobalt-ammine could persist through various combinations 

 with different acids, but also proved that certain acid groups, 

 like NO2, must be frequently considered an integral part of 

 the base, and that this was notably true of the water, con- 

 sidered by others mere crystal- water, which distinguished the 



