The elements of physiology / by J. Fred Blumenbach.

  • Blumenbach, Johann Friedrich, 1752-1840.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: The elements of physiology / by J. Fred Blumenbach. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    12. The cruor has many peculiarities, in regard to both the colour and the figure of its particles. It consists of globules, which in recent blood are of a con- stant form and size, and said to be 3-3*0 0 of an mcn m diame- ter. Their form, indeed, has been a subject of dispute, but I am disposed to consider it as much more simple than some writers of great celebrity have imagined. I have always found it globular, and could never discover the lenticular shape which some have asserted that they remarked. It has been likewise advanced, that the globules change their form while passing through a vessel of very small capa- city, — that, from being spherical, they become oval; and, when they have emerged into a vessel of larger area, that they resume their globular shape.s This, although I would by no means deny it, I cannot conceive to occur during the tranquil and healthy motion of the blood, but should refer it to a spasm of the small vessels. Their globular figure can be seen in a living animal only, or in blood very recently drawn : for they are soon unobserv- able, becoming a shapeless mass which resembles serum in every circumstance excepting colour. h 13. Their colour is red, and from it is derived the colour of the blood. In intensity it varies infinitely; paler in ani- mals which have been poorly nourished or have suffered from haemorrhage; more florid, when oxygenised * (rendered arterial, to use the common phrase) by exposure either to 6 G. Chr. Reichel, De sangui?ie ejusque molu experimental. Lips. 1767. 4to. p. 27. fig. 3. g.g. h Consult Ever. Home, Phil. Trans. 1818. P. I. p. 172. ' Unwilling as I am to follow the example of those who, especially in mo- dern times, delight in changing scientific terms, I cannot but think that the words oxygenised and carbonised may be advantageously substituted for arterial and venous: because arterial blood is contained in some vessels called veins, v. c. the pulmonary and umbilical ; while, on the other hand, venous blood is contained in the pulmonary and umbilical arteries. In the same manner, the veins of the chorion in the incubated egg contain arterial; and the arteries, venous blood j — to use these expressions in their common acceptation. But we shall treat of the doctrine of the relation of oxygen and carbon to each kind of blood, in the section on respiration.