O Plimmer S^ Scott (chick) 

 ® Calculated from the nVjclein N data 

 of LeBreton Sz Schaeff6r and Targonski, 

 and lipoid P of Cahn (chick) 



• Javillier, Allaire 

 and Rousseau (mouse) 



1214 METABOLISM OF LIPOIDS, STEROLS, [pt. iii 



called the "active phosphorus". As Table 175 shows, the mammals 

 and invertebrates can hardly be compared except in this way, but 

 when it is done it is found 

 that the mammal comes inter- ^^^^r 

 mediate between some of the 

 invertebrates as regards its phos- 

 phorus distribution. It does not 

 seem possible to draw any onto- 

 genetic conclusions from this 

 body of data, but it is as yet, of 

 course, very restricted. 



The undeveloped egg of the 

 bird has, as would be expected, 

 a phosphorus distribution very different from any tissue, and even the 

 body of the 14-day chick is not very like any of the adult tissues of 

 the bird (we only have figures q_ 



2 



Days-5 



Fig. 384. 



for the pigeon). The nuclem 

 phosphorus/lipoid phosphorus 

 ratio is interesting. The values 

 for the chick placed in Table 1 75 

 are taken from Plimmer & 

 Scott's figures for the phos- 

 phorus distribution in the em- 

 bryo, and these authors, as I 

 have before remarked, did not 

 give their figures in milligrams 

 per embryo, or even per cent, 

 of the weight of the material. 

 Thinking therefore that a cal- 

 culation based on percentages 

 of the total phosphorus alone 

 might be distorted, I calculated 

 the nuclein phosphorus in the 

 embryo (which has never been 

 directly estimated) from the 



Targonsk 



Days 



Fig- 385- 



data of LeBreton & Schaeffer and Targonski for the nuclein nitrogen 

 in the embryo, and in this way obtained the nuclein phosphorus/lipoid 

 phosphorus ratio for each day during the last fortnight of development. 

 The result, given in Fig. 384, shows first a rise and then the beginning 



