i6 PROTOPLASM 



nioiiia," as an example of similar desolution processes. My 

 interpretation of the formation of droplets in oil, obtained 

 quite independently, thus harmonises in essentials with 

 Schwarz's ideas. I can also cite as a good example of such 

 a process of desolution, connected with the formation of 

 frothy structures, the behaviour of the mixture of collodion 

 solution and clove oil usually employed for fixing sections 

 on the slide. This mixture, when spread out into a thin 

 layer on the slide, usually shows a beautiful finely frothy 

 ■ structure after hardening and removal of the clove oil by 

 means of turpentine. By colouring the frothy collodion 

 membrane with aniline stains the structure can generally be 

 easily studied. Its great resemblance to the fine reticular 

 structures of protoplasm makes this method of sticking on 

 sections seem not without its dangers in investigations of 

 protoplasmic structures. What is the exact course the 

 process of desolution takes in this case I have not investigated 

 more closely, but probably the warming of the mixture, as a 

 result of which the solvent medium common to both the 

 collodion and the clove oil is driven off, leads to the 

 separating out of the latter in the form of minute droplets, 

 until the stiffened layer of collodion finally obtains the 

 frothy net-like structure. 



After determination of the important influence of soap 

 on the formation of froth in the oil, it naturally fol- 

 lowed that the employment of a salt suitable for producing 

 soap, such as K^COg, would cause the process to go on much 

 more energetically and better. Experiments also showed 

 the correctness of this supposition. By such a method not 

 only were the most regular and finely structured froths 

 obtained, but also a series of important facts upon pheno- 

 mena of movement and other matters were ascertained in 

 drops of these froths. 



With further experiments, however, it was soon found 

 that the nature of the oil is of great and all -important 

 influence upon the formation of good and finely-structured 

 drops of oil-lather. A fortunate chance had originally 

 brought into my hands an olive oil that had stood for a long 

 time in a little bottle, and which happened to be just in the 



