304 Fischer's Thcory of Ederna [Dec. 



Ignorant, but for the most part their ideas regarding it have been vague. 

 All the more credit, therefore, belongs to Jacques Loeb^"' and after him 

 to W. B. Cannon," who not only first tried to prove through experi- 

 ment that the problem of edema is essentially a problem of the tissues, 

 but suggested for its explanation a physico-chemical force (osmotic 

 pressure) which if not adequate was at least of such a nature as could 

 be conceived active in the living body. (Page 209.) 



Fischer's detailed presentation of his extension of Loeb's theory 

 of edema is concluded with the following paragraph : 



What now has been accomplished by this finding that the amount of 

 water held by the tissues is essentially an expression of their colloidal 

 State? Its Chief virtue lies in this: It places the problem. When we 

 speak as we have done throughout this paper of the " affinity " of the 

 colloids for water, we have not used this word unthinkingly. An affinity 

 is not a clearly defined force, but we have chosen it to cover a present 

 lack of knowledge concerning the nature of the forces underlying this 

 very important relation existing between a (hydrophilic) emulsion col- 

 loid and the water it contains. Physical chemistry has not yet settled 

 for US what this is, but toward the answer to this question it is now 

 striving. When it is obtained we will have to strike out this mysterious 

 word "affinity" and write into its place the names of such clearly de- 

 fined forces as physical chemistry may choose to dictate. (Page 209.) 



The writer's comment on Fischer's work. The foregoing 

 quotations from Fischer's book have been carefully selected to the 

 verge of redundancy in order to afford a clear and complete concep- 

 tion of the collochemical theory of edema as Fischer has formu- 

 lated it. Fischer has given new force and more pregnant significance 

 to some well known but frequently disregarded facts, and his work 

 will receive sympathetic study wherever colloidal properties are 

 comprehended and appreciated. 



" Loeb : Pflüger's Archiv, 1898, Ixxi, p. 468. 



^Cannon: American Journal of Physiology, 1902, vi, p. 91. Cannon showed 

 that the cause of increased intracranial pressure after injury is dependent upon 

 changes in the tissues of the brain itself which enable this organ to absorb an 

 increased amount of water. He interpreted his findings as in favor of Loeb's 

 ideas of edema. They are more readily interpretable on the basis of our col- 

 loidal conceptions of edema. Had Cannon's results received the recognition 

 which their worth merits, pathologists, clinicians, and surgeons in their discus- 

 sion of the source of increased intracranial pressure would not still be seeking 

 in blood pressure the origin of a force greater than itself, for the swelling 

 brain is able to shut off its own arterial blood supply. 



