INTRODUCTORY 7 



The phenomena of chemotaxis, of anaphylaxis, and of the 

 activities of ferments and toxins, all illustrate the importance 

 of the " chemistry of imponderables." Richet lays stress on 

 the significance of individual humoral differences. " Every 

 illness, every intoxication, has caused the formation, perhaps 

 the destruction, of a certain substance in the blood, and has left 

 its natural trace a trace which is not effaced by years. Just 

 as there is a psychological memory facts which are present 

 to the consciousness so there is a humoral memory of all 

 preceding injections. As these injections differ in each person 

 in intensity, quantity, and duration, it follows that each 

 person differs from every other in the chemical properties of his 

 blood." 



The irritability which rules the functions of the nervous 

 system is in itself a chemical phenomenon. Richet says : 

 ' ' The living being is a chemical mechanism, and perhaps it is 

 nothing more." Such a sentence by an eminent modern 

 physiologist illustrates the trend of present-day physiology. 

 The attitude is reminiscent of that which became prevalent in 

 the earlier days of Huxley's work. The modern view of 

 " protoplasm "is, however, very different from the original one, 

 and the chemical attitude, critically restrained, may possibly 

 do more to explain the processes of life than all the painstaking 

 anatomical, microscopical, and mechanical investigation of the 

 past fifty years. 



The theoretical basis for opotherapy and the practical value 

 of this method of treatment has varied very considerably in 

 different cases. Some flagrant examples of uncritical applica- 

 tion of the method are the treatment of heart disease by extracts 

 made from heart muscle, subcutaneous injections of extracts of 

 ciliary bodies in iritis, and of synovial membranes in diseases 

 of the joints. 



Long ago the conception was formulated that "each single 

 part of the body, in respect of its nutrition, stands to the 

 whole body in the relation of an excreting organ."" The 

 term "excreting " was here used in Johannes Miiller's sense 

 (vide supra, p. 2), and is practically synonymous with the 

 modern " secretion." It is certain that the organs of the body 

 produce effects upon one another in many different ways by, 

 means of the products of their metabolic activity. Conveyed 

 in the blood-strearn to different parts of the body, these pro- 



