1200 METABOLISM OF LIPOIDS, STEROLS, [pt. iii 



They concluded that the differences were within their experimental 

 error, and that the shell did not provide any phosphorus for the 

 egg-interior. 



Carpiaux in 1908 made a certain number of shell-analyses with 

 the following results : 



Carpiavix Burke, Pinckney & Jones 



% dry weight % dry weight 



Unincubated Incubated Unincubated Incubated 



Calcium oxide 54"30 54'86 52-69 52-77 



Phosphorus pentoxide ... 0-31 0-32 0-371 0-403 



The ratio calcium/phosphorus was therefore in the former case 

 i75'i/i-o, and in the latter case i74-i/i-o. The amount of phos- 

 phorus taken from the shell must then be very minute, for according 

 to other data of Carpiaux the shell loses 162-2 mgm. of calcium oxide 

 to the egg-interior during the 21 days, and, as the calcium/phosphorus 

 ratio in the shell is almost identical before and after, the phosphorus 

 lost, if any, must bear the same ratio to the calcium lost, i.e. 175 to i, 

 which would work out at not more than o-g mgm. of phosphorus 

 pentoxide. Finally Harcourt & Fulmer in igoSjDelezenne & Fourneau 

 in 1918, and Burke, Pinckney & Jones in 1925 showed absolutely no 

 increase in total phosphorus of the egg-interior during the 2 1 days 

 of development. 



Plimmer & Scott made use of the following classification of phos- 

 phorus fractions : 



(i) Inorganic phosphorus soluble in water and acids^. 



(2) Organic phosphorus compounds, soluble in water and acids, 

 i.e. guanylic acid, inosinic acid, phosphocarnic acid, free glycero- 

 phosphoric acid, hexosephosphates and all similar bodies. This frac- 

 tion would also include pyrophosphate. 



(3) Compounds such as lecithin and kephalin soluble in ether. 



(4) Nucleoproteins and similar bodies insoluble in water. 

 (5! Phosphoproteins and similar bodies insoluble in water. 

 Plimmer & Scott extracted the eggs and embryos with ether, alcohol, 



I per cent, hydrochloric acid, distilled water, etc., and then estimated 

 the inorganic, organic, and total phosphorus by the Plimmer-BayHss 



1 It should be emphasised that organic phosphorus compounds of a labile character 

 such as creatine-phosphate, which have been discovered since 1909, would appear in 

 this fraction. An investigation of the appearance of these in the chick embryo is urgently 

 needed. 



