the 'Blood in some Mammi/era. 865 



This exception, then, to the generaFrule, deduced from the 

 observations of MM. Prevost and Dumas, does not exist in 

 reality, and new microscopical researches on the physical con- 

 stitution of the blood, made by a great number of physiologists 

 in Germany, England, and France, have successively enlarged 

 the bases on which it rested. MM. Prevost and Dumas had, 

 it is true, established the existence of circular globules in the 

 embryo of the chick during the early period of incubation ; 

 but, in animals which have already passed the period of the 

 metamorphoses characteristic of the embryo state, no simi- 

 lar anomaly was known, and after a considerable number of 

 particular observations already collected, it appeared to be a 

 legitimate conclusion that, in vertebrated animals, the blood 

 with circular globules belongs essentially to the mammifera, 

 and that the blood with elliptical globules was peculiar to the 

 aves, reptilia, and pisces. Now, these two groups of vertebra- 

 ted animals differ also from each other in their mode of repro- 

 duction, and it was not uninteresting to observe that the blood, 

 in all oviparous vertebrated animals, differed by so clear cha- 

 racters from that of the vertebrated provided with mammas. 



M. Wagner, in a recent publication, has announced that, in 

 the lamprey, the globules of the blood are circular ; but the 

 lamprey is a fish so abnormal, and appeal's in so many rela- 

 tions to approach to invertebrated animals, in which the solid 

 corpuscles suspended in the nourishing fluid are also cu'cular ; 

 that this exception seemed to be explained by the natux'e CA'eu 

 of the animal in which it was found, and did not appear to be 

 sufficient to diminish the importance attached to the differences 

 of forms, already observed in superior animals, between the glo- 

 bules of the blood of the mammifera and oviparous vertebrata. 



Such was the state of this point of science when M. Mandl 

 presented to the Academy the note of which we are going to 

 give an account, and if we have entered into these historical 

 details, a little too minutely perhaps, it is because they appeai'ed 

 to us necessary in order to make us duly appreciate the inter- 

 est of the new observations submitted to our examination. 



By pursuing researches on the microscopical characters of 

 different organic tissues, researches Avhich he proposes to col- 

 lect into one work, some parts of which are already before 



VOL. XXVII, NO. UV. OCTOBER 1839. B b 



