68 Zoological Society : — 



to tne the explanation least open to objections. It might be con- 

 ceived that the cells enlarged by imbibition, until at length the less 

 distensible inner membrane gave way, and permitted an extravasation 

 of a portion of the cell-contents between it and the outer membrane, 

 its own continuity being in the meanwhile instantaneously restored 

 by cohesion of the ruptured borders*. In this way a microscopic 

 drop of the cell-contents would be lodged between the outer and 

 inner membrane, and completely severed from the general cell-cavity. 

 The peculiar modification spoken of as the "hooded" appearance 

 might be due to imbibition of fluid between this microscopic drop 

 and the outer envelope. 



The chief difficulties in the way of this explanation arise out of 

 the differences of nature which appear to exist between the projection 

 and the general cell-contents of which it is supposed to be a detached 

 portion. The projection refracts light much more highly than the 

 cell-contents ; it also is deeply dyed by magenta, whereas the cell- 

 contents are only very feebly so. 



In conclusion, it may be added that important advantages may be 

 expected from the use of magenta in histological researches. Its 

 inert chemical character, its prodigious tinting power, and its solu- 

 bility in water eminently fit it for such a purpose. It will probably 

 prove of especial use in bringing into sight objects which otherwise 

 evade the visual organs from their absolute colourlessness and trans- 

 parency, and from the equality of their refraction with the medium 

 in which they exist. 



ZOOLOGICAL SOCIETY. 

 June 24, 1862.— E. W. H. Holdsworth, Esq., F.L.S., in the Chair. 



On the Breeding of the Nutcracker (Nucifraga caryo- 

 CATACTEs). By Alfred Newton, M.A., F.L.S., F.Z.S. 



About six months ago (P. Z. S. 1861, pp. 396-7), I expressed a 

 hope of being able before long to give the Society some more certain 

 information with respect to the breeding of the Nutcracker {Nuci- 

 fraga caryocatactes). In that I hope I have not been altogether 

 disappointed. 



The nest and young bird now exhibited (the latter still showing 

 traces of its original downy clothing) have been received by me 

 within the last few days from my excellent friend Herr Pastor P. W. 

 Theobald of Copenhagen, to whom I think the Society will join with 

 me in hearty congratulations on his success in obtaining these deci- 

 sive facts in regard to the nidification of this mysterious bird, and 

 whose zeal in the quest of zoological discovery fully deserves, in my 

 opinion, all the praise that can be accorded to it. 



* In the same manner as a soap-bubble when bisected, instead of collapsing, 

 forms, in virtue of the adhesiveness and fluidity of its envelope, two new and per- 

 fect bubbles. That the cell-wall of the blood-disk possesses some such endow- 

 ment seems highly probable. I have on several occasions witnessed, after adding 

 magenta, the total extrusion of the nucleus, both in the frog and in the newt, 

 without the least collapse of the corpuscles. 



