No CrossRef data available.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 17 January 2013
In the Transactions of the Royal Society for 1778, Mr Hunter has given an account of some experiments which he made on the freezing of the egg of the common fowl, from the results of which he inferred,—“That the fresh egg has the power of resisting heat, cold, and putrefaction, in a degree equal to many of the more imperfect animals, …. and that it is more than probable, this power arises from the same principle (a living principle) in both.”
page 505 note * Mr Paget assigns for the freezing-point of the egg a temperature of 32°, or between 31° and 32°, and supposes that it cannot fall below that, unless at perfect rest; he says,—“ That the egg should be unmoved, and that its albumen should be not even so much disturbed as by the introduction of the thermometer.” My results, as will be seen nowise accord with this.
page 506 note * From such observations as I have made, this filamentous cellular structure of the albumen differs but little from fibrin; it appears to possess the same contractile quality. (See the author's “Physiological Researches,” p. 422.)
page 507 note * The fœtus, well detached from the vitellus and the membrane, weighed 27.3 grs. The allantois or membrane next the shell, was highly vascular, as was also the vitelline membrane, their vessels conveying red blood of a florid hue. The red corpuscles were, for the most part, of the form of those of the adult fowl; some were circular and yet nucleated; these were of a larger size. The fluid between the allantois and the yolk was slightly coloured reddish, from blood corpuscles suspended in it, from the rupture of some vessels. It was limpid, very dilute, contained little or no albumen. When heated to the boiling point, it was not coagulated, nor did it become even milky, merely a minute portion of greyish matter subsided, no more than might be referred to the blood corpuscles. It had a strong alkaline reaction. 28.2 grs. of it, evaporated to dryness, left only .3 gr. of solid matter, or 1.06 per cent., consisting chiefly of common salt and an alkaline carbonate. Contiguous to the yolk, and contained within its vascular membrane, there was some very tenacious transparent albumen, of faintalkaline reaction. By heat it was coagulated; the coagulum was milk-white, unusually dense and firm. 57 grs. of the viscid matter, evaporated to dryness, afforded a residue of 14.7, or 25.8 per cent. The yolk consisted of a thin and thicker fluid, both of which showed a faint alkaline reaction. A mixture of the two was of the sp. gr. 1022; of the thin kind, 33.9 grs., evaporated to dryness, were reduced to 8.6 grs., or 25.3 per cent, ofthe thicker kind; 30.4 grs. evaporated to dryness were reduced to 9.3, or 30.6 per cent. The eyes of this fœtus were fully formed; the lens of each, resting on the crystalline humour, was .133 of an inch in diameter, a perfectly transparent sphere.
page 508 note * The appearance of the yolk of the newly laid egg, and of that from lime-water, kept about twelve months after being boiled, slightly differed; that of the latter was of a paler and less bright yellow. In both eggs, between the yolk and the white, there was a greyish discoloration. The quantity of air that was disengaged from the egg long kept was remarkable. I supposed that it might be carbonic acid or azote; but from one examination I made of it, it appeared to be merely common air. Owing to this circumstance, eggs thus kept, or kept long otherwise, crack, and sometimes with a little explosion, when put into boiling-water; the newly laid, which contain very little or no air, not being subject to the same effect,—the exemption may be held to be characteristic.
page 512 note * Are, it may be asked, the above indications sufficient ? In two instances I have found specks of blood on the membrane of the yolk of the newly laid egg. In that of the last, I examined the blood, and found it to contain well formed, elliptical nucleated corpuscles similar to those of the adult fowl; the inference made was, that the blood was derived from the oviduct in the descent of the yolk. As to the enlargements of the cicatricula, its evidence seems less open to objection; and yet, without a large comparison, can it be said with certainty, that the size was the result of increase from development? I have found the cicatricula of a newly laid egg that had been frozen, apparently a little enlarged.
page 513 note * In one of these only, were there marks of incipient putrefaction. It is noteworthy, that in three of these, the albumen was firmly coagulated, as if it had been boiled; it was quite white, and showed its usual alkaline reaction. The yolk was also coagulated, but less firmly. Mr Hunter states (op. cit. p. 29) “that if an egg was not hatched, that egg became putrid in nearly the same time with any other dead animal matter.” This does not accord with the results just mentioned, nor with others which I have obtained. In many instances I have found the aborted eggs free from putridity after incubation; whether an embryo could be detected or not, there was commonly a blending of the yolk and white, and the formation of a fluid, almost entirely destitute of viscidity. Such an admixture is certainly favourable to the putrefactive change.
page 513 note † Phil. Trans., for 1778, p. 34.