THE FLUIDS OF THE EGG. 353 



THE FLUIDS OF THE EGG. 



WHILE investigations in reference to the egg and its morpho- 

 logical elements, its development, and metamorphosis, have led to 

 the most brilliant discoveries in physiology? the composition and 

 character of the animal egg and its constituents have met with 

 little attention from the chemist, and perhaps not without reason, 

 for other fields of inquiry, alike more accessible and more extensive, 

 promised to yield a far richer harvest than could be anticipated 

 from the investigation of this subject. An inquiry into the con- 

 stituents of the egg is still deficient in those preliminary investiga- 

 tions, which are necessary for the cultivation of the subject in such 

 a manner as to correspond to the general advance of science and 

 the present stage of histological discovery. Thus, for instance, 

 although our knowledge of the fats is undoubtedly much advanced, 

 and has attained a certain decisive stage, we are still wholly ignorant 

 of many of the animal fats and of their relations to the lipoids. 

 Our physiological enquiries have, however, shown us that the fats 

 participate largely in promoting the growth and metamorphosis of 

 the egg. Considerable obscurity still attaches to the chemical 

 investigation of the various matters containing phosphorus, which 

 occur, as it would appear, with the same constancy in the egg as 

 in the brain and spinal cord. 



We have already frequently spoken of the deficiency of our 

 knowledge of the protein-bodies. Inquirers have scarcely ventured 

 till the most recent times to hazard a conjecture as to the presence 

 of other non-nitrogenous matters, as for instance, sugar, in addition 

 to the fats in the fluids of the egg. 



Under the term " fluids of the egg/ 5 we also usually include 

 those fluids which are coeval with the development of the embryo, 

 but which we shall not take into consideration in the present 

 place, since we treat of the liquor amnii under " Transudations," 

 of the liquor allantoidis under "Urine/' of the vernix caseosa 

 under "Cutaneous Secretion/ 5 and of the gelatin of Wharton* 

 under " Mucus/' 



As the eggs of most animals are either very small or cannot 



* [The gelatin of Wharton is the limpid fluid with which the cellular tissue, 

 that unites the vessels of the umbilical cord with, the amniotic,' investment, is 

 impregnated. G. E. D.] 



VOL. II. 2 A 



