120 M. Dumas on the Constitution of Milk and Blood. 



base towards the tip. The shaft is yellowish white for about 

 half its lengtli from the base, with a line of dark brown along 

 the side next to the inner web, becoming generally darker 

 brown as it approaches the tip. 



The general colour of the tail-feather is dark ashy grey, 

 becoming reddish on the outer and brownish on the inner web, 

 dotted throughout with small white spots. Along both webs, 

 near the shafts, extending from the base for two-thirds the 

 length of the feather, are numerous rather large reddish spots 

 with black centres, generally of an oblong form, but lengthened 

 out into lines towards the margins ; near the tip these 

 reddish markings disappear entirely. The shaft is reddish, 

 blackish brown on the side of the outer web. The feather is 

 very broad, graduating to a sharp point at the tip ; its total 

 length is about 4^ feet. 



These feathers do not resemble in any particular that of the 

 A. hipunctatus described lately by Mr. Wood. I shall give 

 full-size representations of all the feathers in my Monograph 

 of the Phasianidae, now publishing. 



XVII. — On the Constitution of Milk and Blood. 

 By M. Dumas*. 



DuEiNG the most troubled years of the first French revolution, 

 the old Academy of Sciences of Paris having been suppressed, 

 its members none the less continued their patriotic coopera- 

 tion in the labours required by the new necessities of the 

 country. History has given them credit for this. It associates 

 the names of the principal of them with those of the illustrious 

 administrators and generals, who then caused the integrity of 

 the French soil to be respected. 



The editors of the ' Annales de Chimie,' who had been com- 

 pelled to suspend their publication under the reign of Ten-or, 

 on resuming it had the happy thought of collecting, in two 

 volumes, all the memoirs or reports with which the Academi- 

 cians had been charged. In running through these we appre- 

 ciate at a glance the importance of the questions which were 

 addressed to them, the insufficiency of the means at their 



* Translated by "W. S. Dallas, F.L.S., from the ' Bibliotheque Univer- 

 selle,' 15 June 18*71, Archives des Sciences, pp. 105-119. This paper has 

 been extracted from the ' Philosophical Magazine ' for August, as, although 

 its subject does not strictly belong to natural history, some of the author's 

 observations will be of interest to naturalists at the present time. 



