50 PHYSICAL CHEMISTRY IN MEDICINE. 



been considered as sufficient evidence for the primary 

 coagulation structure of all solid colloids. 



III. 



The beginning of those investigations of BUTSCHLI on 

 colloidal structures which must be considered in the gen- 

 eral question that lies before us were observations on 

 microscopic foams of gelatine and olive-oil, which when 

 properly prepared furnish a framework of solidified gela- 

 tine walls in the chambers of which is inclosed the fluid 

 oil. 



BUTSCHLI found that the structures which can be 

 obtained through typical coagulation of colloids are also 

 built according to this plan. Thin layers of egg albumin 

 coagulated through heat or those precipitating agents 

 which are generally known as "fixing-agents, " or aca- 

 cia solutions precipitated with alcohol, precipitated 

 liquid (peptonized) gelatines, etc., all show under the 

 microscope the same characteristic, finely honeycomb 

 structure. Up to this point the conclusions of the Heidel- 

 berg zoologist, which are of great interest to the molecular 

 physicist also, show a complete harmony between obser- 

 vation and interpretation; and the value of BUTSCHLI'S 

 discoveries for the morphologist who utilizes analogous 

 methods to render apparent cell structures is not to be 

 underestimated. 



In the further course of his observations on colloids 

 BUTSCHLI later concludes, from a study of substances in 

 the condition of swelling (jellies), that these also have a 

 true honeycomb structure identical with that observed 

 in coagulation foams and in typical coagulations. Only 



