of Phosphorus in Animal and Vegetable Tissues. 479 



believes, necessarily indicate the existence of a nucleo-proteid in 

 them, for Dr. Elliott has found that they digest in artificial gas- 

 tric juice, leaving no residue, which would not be the case were a 

 iiucleo- compound present. 



The outer portions of the rods and cones in MenobrancJius and 

 Diemyctylus are rich in organic compounds of phosphorus. It is 

 more abundant in the rods than in the cones, and it is not due to 

 lecithin, for the retinae used were freed from the latter, nor is it 

 owing to the presence of inorganic compounds of phosphorus, for 

 the reaction is not obtainable during the first twenty minutes after 

 placing the organs in the nitric-molybdate solution, while it is a pro- 

 gressive one up to the sixth hour. The chromatin of the nuclei of 

 all the layers of the organ also gives the reaction. 



The chromatophore in Spirogyra gives a weak phospho-molybdate 

 reaction, and it appears to be due to the presence of an organic com- 

 pound of phosphorus. A more marked reaction, however, is usually 

 found in the pyrenoids in the same genus, and also in those of (Edogo- 

 mum, Cladophora, and Conferva. In fresh specimens of Spirogyra, 

 taken during daylight and put into the nitric-molybdate reagent, the 

 pyrenoids appeared to give a stronger reaction than those of 

 specimens taken at ten o'clock at night. The reaction develops 

 slowly. 



A diffuse reaction for phosphorus, slow in developing, was obtained 

 in the cytoplasm of Saccharomyces Ludwigii. In apparently normal 

 cells this may be the only reaction which will be obtained, but in 

 cells cultivated in the sap of the iron-wood tree a spherical body 

 occurs, at first sight like a nucleus, but frequently homogeneous, which 

 after about ten hours' treatment with the nitric-molybdate reagent 

 gives a reaction for phosphorus which may be very marked. This 

 body is in no sense a nucleus,* nor does the phospho-molybdate reac- 

 tion reveal any structure that corresponds to the latter. The fact 

 that the " masked " iron in these cells has a distribution parallel to 

 that of the organic phosphorus, also points distinctly to the absence 

 of a nucleus. 



In Cyanophycese the " central body " always gives evidence of the 

 presence of organic phosphorus compounds. A stronger reaction 

 for phosphorus was obtained in the iron-holding, chromatin-like 

 granules which are to be found in the central body, or on its peri- 

 phery, in Tolypothrix and Oscillaria. The " cyanophycin " granules, 

 on the other hand, have not given any evidence of the presence of 

 organic phosphorus except in some few filaments of a preparation 

 of Oscillaria tennis, in which case a marked reaction was developed 

 in about an hour. 



* I hare discussed the nature of this body, ' Quart. Joum. Micr. Sci.,' voL 

 38, p. 246. 



