274 THE PHYSIOLOGY OF REPRODUCTION 



give a blue colour. Their solutions in alcohol, ether, or chloroform 

 are further characterised by the absorption-spectrum, 1 which shows 

 two bands in the blue part of the spectrum (between the lines F and 

 G). The Interns are usually associated with the fatty substances, i.e. 

 true fats and lipoids, in their distribution. The corpus luteum is 

 rich in fatty substances deposited in the cells in the form of numerous 

 relatively large globules. The morphological appearance of the hitein 

 cells is therefore similar to that of the adrenal cortex and the glandular 

 adipose tissue. This similarity extends to the nature of the fatty 

 substances present. These are coriiposed partly of true fats and partly 

 of lipoids, among which cholesterin and its esters can be identified 

 most readily. Phosphatides (lecithin) and cerebrosides, either free or 

 in combination with sphingomyelin, are also present. 



The estimations of Iscovesco 2 and of Chauffard 3 and his col- 

 laborators have given quantitative data from which the following 

 table has been calculate d for the sow : 



The figures represent averages, and the individual estimations 

 show considerable variations, since the lipoid content of the corpus 

 luteum varies with its functional state. Chauffard and his 

 collaborators distinguish three stages in the evolution of the corpus 

 luteum for which they give the following average figures : 



Initial hsemorrhagic stage 

 Mature stage 

 Regressive stage Ji. ? 



Cholesterin Content. 

 1 '99 per cent. 

 5-84 '' 

 10-92 



Observations on the phosphaticles of the corpus luteum of the sow 

 during pregnancy 4 indicate a diminution as pregnancy advances. In 



1 Thudichum, " Uber das Lutein und die Spektren gelbgef arbter organischer 

 Substanzen," Centralblatt f. d. med. Wissenschaft^ vol. vii., 1869. 



2 Iscovesco, " Les lipoides de 1'ovaire," Comptes rend. Soc. de Biol., vol. Ixxiii., 

 1912. 



3 Chautfard, Laroche et Grigaut, " Fonction cholesterinogenique du corps 

 jaune," Comptes reiid. Soc. de Biol., vol. Ixxii., 1912. 



4 Corner, " Variations in the Amount of Phosphatides in the Corpus Luteum 

 of the Sow during Pregnancy," Jour. Biol, Chem., vol. xxix., 1917. 



