[Vol. 2 



244 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



The first naturalist who turned his attention to the great 

 importance of colloidal substances in cells was Biitschli, the 

 zoologist of Heidelberg. A great number of his admirable 

 papers deals with the microscopical features of cell plasma, 

 which he described as a framework of jelly-like substances 

 containing interstices, or meshes filled with fluid substances. 

 Biitschli emphasized the view that the foam structure de- 

 scribed by him is not peculiar to living matter, because a mix- 

 ture of oil and gelatin solution shows the same microscopical 

 structure which he attributed to protoplasm and to all colloids. 



But later on it became more and more probable that such a 

 foam structure in protoplasm indicates nothing more than 

 certain gross features which are by no means identical with 

 the real colloidal structure of plasmatic constituents. Not 

 even in gels, or solid colloids, apparently, is the foam structure 

 a dominant characteristic. Zsigmondy's recent work on gela- 

 tinous structure clearly showed that while forming the gel the 

 colloidal particles, which are distinctly visible in the ultra- 

 microscope, do not arrange themselves in a network, but 

 settle quite irregularly ; so that we cannot assume that meshes 

 are formed in the precipitation of colloids. On the other hand, 

 biologists of rank, as Lepeschkin, after a careful study of 

 the microscopical structure and the physical properties of 

 protoplasm, have arrived at the conclusion that we should 

 not regard it as a foamy mass, or jelly-like substance, but 

 rather as a liquid colloid with the characteristics of protein 

 sols of certain higher concentrations. We can easily confirm 

 the observation that protoplasm, examined by means of the 

 highest power of the microscope, often appears merely as a 

 homogeneous liquid, or transparent mass, sometimes mod- 

 erately turbid from the presence of small distinct drops or 

 corpuscules which are collectively known under the name of 

 ^microsomata." Even though we do not accept Biitschli 's 

 idea with respect to specific structure, we fully share his more 

 general point of view that living protoplasm owes its peculiar 

 activities to colloidal qualities. And this represents our 

 attitude to-day towards protoplasmic investigation. 



