CHAPTER XIV. 



PROPERTIES CONFERRED BY THE COLLOIDAL CON- 

 STITUENTS; CHEMICAL AND BIOLOGICAL. 



EFFECTS OF DISTURBANCE OF THE INORGANIC ENVIRONMENT. 



We have already had occasion to discuss the effects of alteration of 

 the total Concentration of the Environment upon the protoplasm inhabit- 

 ing it, and we have seen that the most salient of these effects depend 

 primarily upon the migration of water into or out of the substance of 

 the cell. The effects arising out of alteration of the normal Compo- 

 sition of the Environment appear to have been first systematically 

 investigated by James Blake, a physician resident in San Francisco 

 in the decades comprised between the years 1870 and 1890. His 

 earliest investigations upon this subject were, however, published in 

 the Archives generates de Medecine and in the Proceedings of the Royal 

 Society of London in 1839 and 1841 respectively; his later and more 

 extensive investigations appeared in the Proceedings of the California 

 Academy of Sciences and in the Comptes Rendus of the French Acad- 

 emy of Sciences. His inquiries into the effect of a variety of inorganic 

 salts when injected into the circulation led to the discovery of a number 

 of important facts; among others to the discovery of the Anesthetic 

 Action of Magnesium Salts to which much importance has been ascribed 

 in recent years. The older generation of physiologists, antedating the 

 modern development of physical chemistry, expressed dosages and 

 concentrations in terms of the absolute weight of substance employed 

 and if, of two substances, a smaller weight of one was lethal than of 

 the other that substance was deemed the more toxic of the two. It 

 was Blake who first pointed out in physiological literature that equal 

 weights of the various inorganic salts do not by any means contain 

 equal numbers of molecules, and he urged that the toxicity or other 

 physiological actions of dissolved substances be referred not to the 

 absolute weight but to the number of gram-molecules of .material 

 administered. Proceeding upon this principle Blake was able to show 

 that many substances hitherto considered to be of very diverse toxicity 

 were in reality very similar in their physiological action. In particular 

 this was found to be the case with many series of Isomorphous Salts 

 of the metals. On the other hand certain metallic salts, hitherto sup- 

 posed to be of like action and toxicity, were found, when tested by this 

 new criterion, to differ very decidedly in their relative effect upon 

 living protoplasm. 



