ON THE MICRO-CHEMISTRY OF CELLS. 471 



detection of potassium and calcium. It was also found that the iron 

 present does not become demonstrable readily in dead nuclei or plasmo- 

 lysed cells until they are allowed to undergo a long-continued decom- 

 position in distilled water. This would seem to indicate that the 

 combination which occurs in the case of calcium and potassium with the 

 living matter is very different from that obtaining between the iron and 

 the nucleo-proteid, chromatin. Everything points to the iron being 

 a definite part of the nubleo-proteid compound during life. It is possible, 

 on the other hand, to explain the masked condition of calcium and 

 potassium during life as due to their existence as free ions protected by 

 the living substance from the ordinary chemical reactions. 



3. In relation to this investigation, but also as the result of an 

 investigation on the composition of the Medusae, Aurelia and Cynnea, in 

 relation to the sea water in which they occur, it was found that the 

 'jelly ' (or Mesogloea of Bourne) in these forms is fundamentally an 

 infinitesimally fine network of an albuminoid, ' discin,' in the mesh spaces 

 of which are contained all fluid and salts derived from the sea water. 

 The albuminoid as it exists in this network is distinct from inorganic 

 substances, and alcoholic specimens of the 'jelly ' when acted on by 

 distilled water for sevei'al days give only a trace of ash. The mesogloea 

 is, therefore, in no sense a true jelly. It may be that the optical appear- 

 ance of a network is really the expression of a foam-like structure, and 

 that thus the 'jelly ' is an emulsion ; but it is safer to compare it to the 

 fibrin of clotted plasma. It is the disintegration of this network that is 

 the cause of the liquefaction of the 'jelly ' in the dead MedusEe. 



These observations suggest that in animal and vegetable cells a similar 

 disposition of the salts present may occur and the proteids holding their 

 solutions, mechanically as in the mesogloea, may be as inert as the 

 ' discin ' of the Medusre. To express it differently, the cytoplasmic 

 network in the living cell may be in many cases a result of the life of a 

 cell, but not evidence of life in the cytoplasm. 



4. Professor Mackenzie has been engaged on the investigation of the 

 occurrence of masked iron and phosphorus in neoplasms, and reports that 

 it will take some months yet to finish his observations, 



The Committee ask to be reappointed. 



Botanical Pliotograplis. — Report of the Committee, considing of Pro- 

 fessor L. C. MiALL (Chairman), Professor F. E. Weiss (Secretary), 

 Mr. Francis Darwin, and Pi-ofessor G. F. Scott-Elliot, appointed 

 to consider and report upon a scheme for the registration of Negatives 

 of Botanical Photographs. 



APPENDIX. — Arrangements in Existence for the Preservation and Ttecjis- 



tration of Pliotograplis of Anthropological and Geological Interest . iiage 472 



The Committee recommend the formation of a register of photographs 

 of botanical interest on similar lines to those already in existe^c^ for the 

 registration of geological and anthropological photographs respectively (see 

 Appendix). 



To carry out such a scheme the Committee should be reappointed, 

 with a small grant. 



