358 THE UNFERTILISED EGG AS A [pt. iii 



the organism other relations are found; thus corpuscles and plasma 

 of some mammalian bloods have converse potassium/sodium ratios, 

 and, as a general rule, potassium preponderates in cells while sodium 

 preponderates in media. Of the anions PO4 usually takes up much 

 the greatest part, but SO4 may in certain cases equal it. In the 

 columns on the right of the table the total anion and total cation 

 are shown, in each case calculated as millimols and as milli- 

 equivalents, the former giving an idea of the total number of 

 molecules present, the latter of the total number of valencies. 

 Study of the anion/cation ratio expressed as milliequivalents per 

 cent, wet weight provides an important key to the constitution 

 of the egg, for it shows roughly to what extent anion or cation is 

 held in combination with protein or lipoid, or other organic sub- 

 stances. We have already seen that in the case of the hen's egg, 

 taking both yolk and white into account, the anion/cation ratio is 

 more than unity (Bialascewicz's figures give 2-17), showing that a 

 quantity of sulphur and phosphorus is in organic combination — a 

 conclusion which fits in admirably with all that we know of the 

 hen's egg from other sources. The same relationship is seen in the 

 figures of Konig & Grossfeld for the three fish eggs they investigated, 

 the pike, the cod and the sturgeon. On the other hand, the figures 

 of Page for two echinoderm eggs give ratios much less than unity, 

 demonstrating the organic combination of a good deal of the cation. 

 It may be noticed that the analyses of Dittmar and Page for sea 

 water give ratios in the very close neighbourhood of unity, as would 

 be expected, and indicate at the same time that the ratio cannot be 

 regarded as significant to less than o-og. From what has been said, 

 therefore, it might be concluded that the yolk-laden eggs of the 

 fishes, like that of the hen, have a ratio above unity, while the 

 alecithic echinoderm eggs have ratios much below it. But there 

 are exceptions to this generalisation. The ratio of unity for the 

 carp egg which is given by Gobley's results may perhaps be 

 neglected, owing to the date of the work (1850), and the similar 

 value obtained by Roffo & Correa on a gastropod egg may 

 also be regarded as suspicious because of the enormous amount of 

 sodium chloride that appears in their analysis. But the careful work 

 of Bialascewicz in 1926 does not altogether support the generalisa- 

 tion. His figures for the fish egg are in good agreement with those of 

 Konig and Grossfeld, but his anion/cation ratios for the echinoderms 



