EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 91 



point of view. Some, however, have considered the numerous che- 

 mical questions full of interest which this examination is capable of 

 resolving. 



" Thus, supposing the chemical analysis of the egg be made at the 

 moment when it is laid, with a view to examine the elements which it 

 absorbs from the air, or evolves during the period of its development 

 when the losses and absorptions of water which it sustains have been 

 determined, and when the whole of the necessary elements have been 

 reunited required the consideration of the chemical processes employed 

 by nature for the conversion of the materials of the egg into the very 

 different products composing the young animal. 



" In applying to the consideration of this question the actual method 

 of organic analysis, the degree of precision which they have arrived at 

 must be given. 



" But, if it be possible, it is desirable to confirm, by ordinary che- 

 mical means, the accounts given of the changes which take place in 

 the proportions of carbon, hydrogen, oxygen, and azote ; and of those 

 relating to the changes of the mineral products which enter into the 

 composition of the egg ; and further, on the other hand, to examine 

 alterations not less important, and capable only of being brought to 

 light by the assistance of the microscope. 



" The Academy desire that, far from endeavouring to confirm, in the 

 several parts of the egg, the presence of the immediate principles which 

 analysis furnishes, the authors should direct all their efforts, with the 

 assistance of the microscope, to the state in which these immediate 

 principles are there met with. 



" Results of a most interesting and important character are antici- 

 pated from this chemical and microscopical examination of the pheno- 

 mena of the production or development of organs. 



" Independent of the study of the development of the foetus in these 

 normal conditions, it is requisite to record the changes that the mo- 

 difications of temperature, or the nature of the medium in which this 

 development is effected produce. The candidates are further required 

 to investigate the incubation of the eggs of birds in several gases ; and 

 in the case of Batrachians, their development in water more or less 

 impregnated with salts, and more or less aerated. 



" The prize awarded will be a gold medal of the value of Three Thou- 

 sand Francs. The memoirs must be forwarded to the Secretary of the 

 Academy before the first of April, 1843. It is requisite for the authors 

 to write their names in a sealed packet, which will not be opened until 

 the Prize Memoir is decided upon." 28th Dec. 1841, p. 1181. 



Coste on Fresh-water Polypi. The researches of the author on these 

 animals are of the greatest importance ; inasmuch as, after having 

 entered upon the complicated organization of the various species of 

 Polypi, the general binary disposition of their organs, the position 

 of their nervous system, and after considering, also, that they have 

 mouths, in many respects analogous to those of the Mollusca, and that, 

 like them, they produce the envelope which protects them ; and when 



