DR. MARTIN BARRY’S RESEARCHES IN EMBRYOLOGY. 
561 
explanation of them. — The newer researches of Schwann appear to give to observation 
another direction, which will perhaps be more productive. It is thus possible, that 
the germinal vesicle is the parent cell for new cells of the germinal membrane. The 
new granulations into which, for instance in Amphibia and Fishes, I saw the ger- 
minal spot to become divided, are perhaps young cells in the parent cell'f~.” The 
facts recorded in the present memoir show this conjecture, so far as it went, to have 
been very near the truth;};. 
418. Richard Owen, with reference to the germinal vesicle of Birds, justly remarks, 
“it is the essential element of the cicatricula, and the centre from which all subse- 
quent development radiates 
419. Allen Thomson. “ The vesicle of PuRKiNJE***has # **received the name of ger- 
minal vesicle, a most appropriate term, since it may be regarded as the more imme- 
diate seat of the germ or germinating faculty of the egg||.” “ We do not know with 
certainty what befalls the vesicle of Purkinje in the ovulum of Mammalia at the time 
of its escape from the ovarium. The analogy of all oviparous animals is strongly in 
favour of the supposition that it bursts in the same manner.** # While therefore, we feel 
disposed to adopt the opinion that the seminal fluid, in fecundating the egg, operates 
its peculiar change chiefly on the germinal part, and that the bursting of the germinal 
vesicle is very probably connected with the change of fecundation, it must be admitted 
that further observations are still wanting to afford a satisfactory proof of the cor- 
rectness of these hypotheses^]".” 
420. Coste, with reference to the germinal vesicle in the ova of Mammalia in general, 
remarks, “ Apres la chute de l’ceuf dans les trompes, on ne voit plus de traces de 
cette vesicule ; nous chercherons a demontrer qu’a la mani&re de celle des oiseaux, 
elle se dissout pour la meme finality With regard to the ovum of the Sheep, the 
same author observes, “ Lorsqu’il tombe de l’ovaire pour penetrer dans les trompes 
ut6rines, la petite vesicule transparente (analogue de la vesicule de Purkinje) se dis- 
sout, et ici encore se trouve confirme ce que nous avous dit d’une manure generate 
de l’oeuf des mammif^res^.” 
420^. Jacquemin. “ La cicatricule et la vesicule de Purkinje sont tres develop- 
pees dans l’ceuf [ Planorbis cornea ] retire de l’ovaire ; ils disparaissent peu a peu pen- 
dant leur passage et leur sejour dans la matrice§§.” “ Le vitellus commence a se trans- 
former en embryon immediatement aprks la ponte — “ Le vitellus, parfaitement 
f Lehrbuch der Physiologie. Erste Abtheilung, pp. 57. 58, 1839. 
X It is due to Professor R. Wagner to mention, that he bad said it seemed to him probable, on many 
grounds, that the germinal vesicle is not a nucleus, as supposed by Schwann (par. 349.) ; and had stated that 
the germinal spot often appeared to him to contain minute nucleoli, as figured, for instance, in his Prodromus 
Historisc Generationis, Tab. II. fig. xxx b. He had also proposed to denominate the germinal spot the “ nucleus 
germinativus” (Lehrbuch, &c. p. 34.). 
§ Dr. Todd’s Cyclopaedia of Anatomy and Physiology, Article “ Aves,” p. 356. 
|| Ibid. Article “ Generation,” p. 452. Ibid. p. 462. ft Embryogdnie Comparee, p. 83, 1S37. 
U Ibid. p. 421. §§ L. c., p. 674. 
4 c 
MDCCCXL. 
