Volume 2

Dissertations relative to the natural history of animals and vegetables / Translated from the Italian of the Abbe Spallanzani ... To which are added two letters from Mr. Bonnet to the author.

  • Spallanzani, Lazzaro, 1729-1799.
Date:
1784
Catalogue details

Licence: Public Domain Mark

Credit: Dissertations relative to the natural history of animals and vegetables / Translated from the Italian of the Abbe Spallanzani ... To which are added two letters from Mr. Bonnet to the author. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    made a perforation in the membrane that in- verts the ovarium, and injedted another drop of feed, which muft have come into imme- diate contadi with the tadpoles. One of the toads died five hours after the operation with the tadpoles in the ovarium, but the other difcharged part of them at the anus imbedded in gluten, as if rtie had been in a ftate of the moll perfedl health. I kept them very care- fully in water, but not one came to perfec- tion ; whence I was obliged to infer, that the gluten is fo indifpenfably necefiary for the nutrition of thefe delicate beings, that fhould it not be prefent at the time of afperfion with feed, they will perilh, even though it fhould be afterwards fupplied. CXXV. Having eftablifhed upon a number of decifive trials, the portability of artificial fecundation with feed (CXIX, CXX, CXXI, CXXII, CXXXIII), I thought of trying whether the exprefied juice of the tefticles would anfwer the fame end. I fuppofed this not unlikely, the tefticles being the organs in which the feed is formed, or rather per- fedted and rendered fit for fecundation -, but on account of their finali fize in this animal, I could not hope to obtain it pure : and my only refource was therefore to fqueeze out the juice, and ufe this for my experiments. The tefticles in the prefent fpecies of toad are fi- tuatedat the upper part of the kidneys ; they have a yellowilh colour and an oval fhape, but are a little gibbous on one fide, like thofq of the cock. At the feal'on of generation they contain a brown, denfe, and fomewhat vifcid liquor. Having colledted a little of this liquor in a watch-glafs, I moiftened with it about