of the Fishery Board for Scotland. 



151 



have stated before, that in the former 24*47 per cent, is inorganically 

 formed, the rest being in organic combination; while in the latter 

 21*22 per cent of the total phosphorus is inorganically formed. 



That is to say, undoubtedly the mass of phosphorus present is in- 

 organic form, but by no means all, either in the unripe or ripe ova. 



The phosphorus which is organically bound is in two forms — viz.,. 

 lecithin and vitellin, and both are more or less firmly attached to one 

 another. 



These two bodies are not simply used up as food stuflfs, but are fore- 

 runners of specific constituents of the embryo. It is very doubtful if 

 there is always in the nucleus of the resting ovum true nuclein of the kind 

 that is met with in the nuclei of pus cells for example. At least I have 

 tried to obtain the decomposition products of the true nucleins from large 

 quantities of ova, but have only obtained small quantities of nuclein 

 bases. 



One point of very great importance with regard to the phosphorus- 

 holding constituents of the ovum is to find out how they are bound, and 

 where they come from. I have tried to find out the origin of the 

 phosphorus of the ovum by first examining the ovarian fluid and then the 

 ova from the same ovary, in order to find out if the bodies in the two 

 were similar or quite distinct in character ; and, in the second place, by 

 employing the method of diffusion, I have tried to find out which of the 

 phosphorus-holding parts pass out, and how they pass out. 



The unripe and ripe ova of the haddock were examined in order to- 

 find out how the phosphorus was bound, and, as I have previously stated, 

 in the former more phosphorus exists in the inorganic form than in the 

 latter, but in both the organically bound phosphorus is present in largest 

 amount. Ripe and unripe plaice ova were allowed to remain in contact 

 with distilled water for prolonged periods, with the result that in both 

 cases phosphorus was found to pass outwards mainly in organic form. 

 Ovarian fluids of the plaice and haddock ripe roes, in addition to those of 

 numerous other fishes, were examined and were found in all cases to contain 

 the phosphorus mainly in organic combination in the form of a body 

 precipitable by acetic acid in the cold, a substance probably of the nature 

 of a nucleo-albumin. In the different specimens I have examined this 

 body contained more phosphorus than the vitellins of the yolk. It is just 

 possible that it is one of the bodies which, by synthesis in the outer parts 

 of the ovum, is formed into vitellin or a forerunner of vitellin (vitellogen).. 



As to whether any inorganically-bound phosphorus is synthetically 

 transformed during maturation into an organically-combined phosphorus- 

 holding body or not, I am still unable to say. It is important to 

 remember that every living cell is so constituted that it can take up from 

 the fluids surrounding it just those constituents which are necessary for 

 its growth, and the medium in which the cells are situated contains those 

 constituents in the proportions most suitable for absorption. 



During maturation the ovum is a miniature chemical laboratory, 

 absorbing oxygen, organic and inorganic substances, and transforming 

 these into bodies suitable either for the nourishment or formation of the 

 embryo. During the growth and maturation of the ovum, a large part of 

 the chromatin of the germinal vesicle may be lost by passing out into the 

 cytoplasm, forming there accessory nuclei, or undergoing regeneration 

 still further in the protoplasm. This is especially well seen in the eggs 

 of amphibia, echinoderms, and some worms. 



It seems to me doubtful whether this is due to the entrance of such a 

 salt as sodium chloride from without, or to the lack of oxygen in the- 



