218 PROTOPLASM 



the coagulation of solid gelatine jelly is difficult to understand ; 

 on the other hand, it is intelligible of itself, if we suppose that 

 the foam structure already existed in the uncoagulated fluid 

 condition, and became visible by coagulation. 



The exceedingly distinct fibrillated alveolar structures alluded 

 to (supra) must lead us to the same supposition. These structures 

 are obtained when filtered albumen is sprinkled by means of a 

 paint-brush into a drop of picro-sulphuric-osmic acid on the slide. 

 The coagulated threads, which one commonly obtains by this 

 method, show, as a rule, as has been said, a very beautiful 

 fibrillated alveolar structure in their longitudinal direction. 

 Now it seems to me most difficult to assume that the fibrillar 

 structure of such threads is first produced by tension of the 

 already coagulated albumen ; on the contrary, I regard it as 

 more probable that the fibrillar structure had already been pro- 

 duced before the coagulation by the drawing out of the fluid 

 white of egg into threads. 



If we further consider that the energetic power of swelling 

 exhibited by albumen and gelatine would gain very much in 

 intelligibility on the supposition of a frothy structure, and that 

 in addition there is the fact that gelatine, at least during the 

 process of taking up water, becomes more or less opaline, and 

 that watery fluid can be squeezed out of gelatine jelly by strong 

 pressure, it appears to me that there is some evidence in favour 

 of the second of these possibilities. I will not omit to point out 

 that neither in the fluid nor in the dried albumen, and still less 

 in gelatine jelly, was any trace of structure to be made out. 

 But it is noteworthy, that in drops of fluid albumen mounted in 

 paraffin oil I was able to observe an indication of an alveolar 

 layer, and even of its radial striation. I put no great value upon 

 this observation, because it requires repeated investigation, and 

 deceptions are very possible. 



Now whether the question that has been raised will be 

 decided in the future in this sense or in another, nevertheless it 

 seems to me at the outset to be of interest, that the foregoing- 

 investigations have led me to a conception of the jelly-like 

 distensible and coagulable bodies, which harmonises well 

 with the opinion expressed by a physicist of experience in 

 this subject. For Quincke has expressed himself upon this 

 point (1890, p. 207) to the following effect: "In the same 

 way I believe gelatinous substances, such as glue and other 

 jellies, should be regarded as fluids in which there are numerous 

 invisible thin partitions of firm or fluid lamellae." 1 I may be 



1 As I see from Lehmann's MoUcularphysMc (Bd. i. p. 525 et scq.}, similar 

 views with regard to the physical constitution of the jellies have already been 



