the Blood in some Mammifera. 367 



that, in order to preserve oiu'selves as much as possible from 

 the causes of error to which observations of this sort are ex- 

 posed, we have examined by the microscope the drop of blood 

 immediately after extracting it, and to retard its coagulation, 

 after extending it in a very thin layer, we have only covered 

 it with a plate of glass, without adding any thing to it. Lastly, 

 our observations have been made with a microscope of Che- 

 vallier, magnifying about 500 times, and our measures have 

 been taken by the aid of a clear chamber adapted to this in- 

 strument. 



We wish we had been able to examine in like manner the 

 blood of the camel with two protuberances, and that of the 

 vigogne, in order to assure ourselves if this character, so ab- 

 normal in the class of the mammifera, is found in all the spe- 

 cies of the family of the camelidae ; but the menagerie does 

 not possess any at present. 



In oxen, sheep, goats, antelopes, and stags, the globules of 

 the blood are circular ; is it the same in the girafe, which, in 

 certain respects, approaches more to the camels ? This ques- 

 tion has appeared to us to merit examination, and to resolve 

 it, your commissioners, in concert with the author of the re- 

 searches, of which we are now giving an account, have submit- 

 ted to microscopical examination a small drop of the blood of 

 the girafe in the Museum, obtained by means of a slight pimc- 

 ture made in the lip of this animal. But the globules did not 

 present any thing particular to us ; they are circular as in the 

 ordinary mammifera, and are in diameter about i^oth of a 

 millimetre. 



Thinking that the blood of the marsupialia might, like that 

 of the camelidae, present some anomaly, we have examined it 

 also in the kangaroo with whiskers. But here, too, the globvdes 

 are circular, and it is only worth while to remark, that their 

 magnitude is less uniform than in most of the mammifera, 

 and that their dimensions have appeared to us to vary be- 

 tween i^jth and ijjth of a millimetre. 



These new facts appear to us to increase the interest of the 

 observations made by M. Mandl ; for they shew how general 

 the tendency of nature is to give to the globules of the blood 



