Observations on the development of the blood corpuscles in the chick, with the various changes which they present from their first appearance to their full development : with some remarks on these changes / by William Macleod.

Date:
[1842]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the development of the blood corpuscles in the chick, with the various changes which they present from their first appearance to their full development : with some remarks on these changes / by William Macleod. Source: Wellcome Collection.

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

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    C)]]SERVATIONS ON THE DEVELOPMENT OF THE BLOOD CORPUSCLES IN THE CHICK. Previous to 18.j8, physiologists were wholly unacquainted with ; any general law by which the development of structure could be • explained. In that year, Schwann of Berlin induced, from the ! generalization of numerous isolated facts scattered through the • various scientific journals, along with his own observations, the ; grand and universal principle, that all organized structures have tlieir origin from cells. ^ Since that year, numerous microscopic ■ observers have increased to a great extent the facts by which the above principle is supported. The following observations are designed to show the manner ■ of formation of one of the bodies belonging to the first class of Schwann’s classification of tissues—the blood corpuscles—with the different changes which they present from their first appear- ance to their full development. These were made on the blood corpuscles of the chick. Before describing the appearances which they present in their process of development, I shall state shortly the manner in whicli these observations were conduct- ed. To get the blood perfectly pure, I removed it from tlie heart of the chick, (this can be done so early as the third day,) so that none of the granules contained in the nutritious matter which surrounds the embryo could enter the blood. I diluted the blood thus removed with fresh filtered scrum. To allow the appear- ances going on within the corpuscle to be seen more distinctly, I used weak acetic acid, which was the only reagent employed. I also examined the blood contained in the germinal membrane and allantois, diluting it with the fluid albumen contained in the ' This statement is not altogether true, as Raspail, in his Organic Chemisln/, has the following sentence:—“ Organization, on the eontrary, is, as it were, a crystalliza- tion which gives a tendoney to assume a vesicular fomi, and produces a cell capable of absorbing the gases necessary both for its vesicular development, and ibr the re- production of otheis similar to it This cell is a laboratory where gases are con- densed into liquids, which in their turn are organized into textures. It is in short, an organized body.”* And in one.of his papers in reply to Dutrochet, published a short time subsequent to his New System of Organic Chemistry, is contained the fol- lowing startling expression. “ Give me a cell eapable of produeing others, anil f will form an organised world.” These are not his exact words, and I cannot at this moment lay my liands on the paper m whieh this remark is contained; but the idea, to which the above sentence gives birth, is the same as that contained in the original.