EXPERIMENTS WITH OIL 7 



results. Drops of such a froth placed under benzin, on 

 quicksilver with which is connected one pole of an induc- 

 tion apparatus, while the other touches the drops, show a 

 distinct spasm at each closing or breaking of the current. 

 I do not, however, believe that this phenomenon is connect) M I 

 with their frothy structure, but that it is to be regarded in 

 just the same way as the alteration in form of a drop of 

 water under similar conditions. 



I was urged to further experiments in manufacturing 

 hue froths by Quincke's communications (1888) on the 

 diffusion of watery fluids through fatty oils. As is well 

 known, the above-named physicist was able to determine by 

 various experiments that such a diffusion may take place. 

 My experiments also, to be communicated in the sequel, are 

 in favour of this happening, or at least are not easily ex- 

 plicable without such a supposition. 



Since Quincke made use of the experience he had obtained 

 with regard to the phenomena of movement, or, more properly 

 streaming, produced by relations of surface tension in fluids, and 

 particularly in oil-drops, in order to construct a hypothesis con- 

 cerning the phenomena of streaming in protoplasm, and took the 

 opportunity of occupying himself more specially with protoplasm 

 in general, it is permissible for me to state more exactly the 

 relations of Quincke's investigations to mine. As I have already 

 remarked, I took from Quincke's work the idea of using fatty 

 oils for the production of finely-structured foams, since I con- 

 sidered possible, as will be presently described, the conversion of 

 the oil into froth by the diffusion demonstrated by Quincke. 

 Moreover, I recognise willingly that Quincke's investigations 

 and hypotheses stimulated me to undertake experiments based 

 upon my own view of the structure of protoplasm, in order to 

 subject the correctness of my conception to a thorough test. On 

 the other hand, my experiments and ideas were, from the very 

 beginning, on an altogether independent footing, the outcome of 

 my experience with regard to the finer structure of protoplasm. 

 The idea of the alveolar structure of protoplasm guided me from 

 the commencement, and, as has been said, prompted the experi- 

 ments. 



I have frequently in conversation communicated my views 

 upon the probable structure of protoplasm to my colleague, Prof. 

 Quincke, and emphasised the fact that certain properties of 

 protoplasm might well be connected directly with this structure, 



