Some experiments on the changes which take place in the fixed principles of the egg during incubation.

  • Prout, William, 1785-1850.
Date:
1822
Catalogue details

Licence: Public Domain Mark

Credit: Some experiments on the changes which take place in the fixed principles of the egg during incubation. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    to conceive how the earth in question can be introduced into the economy of the chick from this source, particularly during the last week of incubation, when a very large portion of the membranes are actually separated from the shell. Secondly, both the albumen and yelk contain, at the end of incuba- tion, a considerable proportion of earthy matter (the yelk apparently more than it did originally); why is this not appropriated, in preference to that existing in the shell ? In opposition to these arguments it will be doubtless stated, that the shell of the egg becomes brittle at the end of incu- bation, and appears to undergo, during that process, some other changes not at present understood. To which it may be answered, that this brittleness has been attributed to the sepa- ration of the membrana putaminis, and the exsiccation of the parts by so long an exposure to the heat necessary to the process of incubation; and in this manner all the known changes produced on the shell by incubation may perhaps be satisfactorily accounted for. Until, therefore, it be demon- strated that some other changes take place in the shell, I con- fess this argument does not seem to me to have much weight. I by no means wish however to be understood to assert, that the earth is not derived from the shell; because, in this case, the only alternative left me is to assert that it is formed by transmutation from other matter; an assertion, which I con- fess myself not bold enough to make in the present state of our knowledge, however strongly I may be inclined to be- lieve that, within certain limits, this power is to be ranked among the capabilities of the vital energies. London: Printed by W. Nicol, Successor to W. Bulmer & Co. Cleveland-row, St. James’s.