ON THE MICUO-CHEMISTKY OF CELLS. 449 



The Micro-cliemislry of Cells. — Report of the Committee, consisting 

 of Professoi- E. A. Schafer (Chairman), Professor E. Kay 

 Lankester, Professor W. D. Halliburton, Mr. G. C. Bourne, 

 and Professor A. B. Macallum (Secretary). (Drawn up hij the 



Secretarif) 



The work of the Committee was directed along the following lines : — 



1. 27ie Localisation of Phosphorus hi the Cell. — In this investigation 

 a wide range of animal and vegetable forms was employed as material, 

 and solutions of molybdate of ammonia in nitric acid were used to localise 

 the phosphorus as a phospho-molybdate compound, the distribution of the 

 latter being revealed after the preparations were treated with solutions of 

 phenylhydrazine hydrochloride. The results show that the element exists 

 in cells in at least five states of combination : (a) As a nuclein or nucleo- 

 proteid in which the phosphorus is firmly combined in both cytoplasm 

 and nucleus, (b) As a derivative (nucleinoid) of nuclein or nucleo- 

 proteid, in which the phosphorus is much less firmly combined. Examples 

 of this are found in smooth muscle fibre in the dim bands of striated 

 mu.scle fibre, in the substance constituting the zymogen granules in 

 secreting glands, and in the outer limbs of the retinal rods and cones, 

 (c) As an inorganic metaphosphate dissolved in the cytoplasm of some 

 cells, and apparently derived from a and b. (d) As lecithin, which is 

 present in every cell, and markedly in nerve tissue, (e) As an inorganic 

 orthophosphate in the tissues of various organs, e.g. liver, spleen, kidney, 

 intestinal mucosa, placenta, itc. In the demonstration of the occurrence 

 of these compounds of phosphorus, the length of time required to demon- 

 strate their presence is an important factor ; and, further, the metaphosphate 

 and orthophosphate may be removed from a preparation in a couple of 

 hours by the action of dilute nitric acid, while lecithin may be extracted 

 by repeated treatment with hot alcohol. By making preparations of cells 

 and tissues with the molybdate method, both before and after the action 

 of dilute nitric acid, as well as before and after extraction with alcohol, 

 it was found possible in every case to ascertain tlie occurrence of one or 

 all of these five classes of compounds in a cellular element. 



This investigation has given a very large number of results which are 

 of too detailed a character to be referred to specially here, and referejices 

 to which are iiow being incorporated in a special j^aper for publication. 

 One generalisation from these observations may, however, be in place 

 here. The organic, usually iron-free, compounds of phosphorus, which are 

 almost universally present in the cytoplasm of nucleated cells, bear a 

 derivative relation to those which ai^e in the nucleus, and which contain 

 ' masked ' iron, while in non-nucleated organisms the comj^ounds of iron 

 and phosphorus are found in the cytoplasm in all cases in a diffused form, 

 but in some also as gi-anules (Cyanophycese and the Yeasts). From the 

 chemical point of view the nucleus is therefore an organ for containing 

 the iron-holding nucleo-proteids, and it is therefore an organ of secondary 

 and later origin in the development of the primal cell organism. 



2. Tlie Relation of the Iron to the other Elements in the Ghrotnatin or 

 Nuclein Molecule. — In this the point to be determined was whether the 

 iron atom is directly united to a carbon atom, as it presumably is in 



1900. 



