FUNCTION OF THE BLOOD-COEPUSOLES. 13 



which show an increase in the number of corpuscles in the blood coming from the spleen 

 and a diminution in the blood of the hepatic veins, are not sufficiently definite to serve 

 as a demonstration that the spleen is a blood-forming organ ; and the same remark 

 may be applied to observations upon the formation of blood-corpuscles by the marrow 

 of the bones. 



In the present state of our knowledge, the following seem to be the most rational 

 views with regard to the development and nutrition of the blood-corpuscles: 



1. At the time of their first appearance in the ovum, they are formed by no special 

 organs, for no special organs then exist ; but they appear by genesis in the sanguineous 

 blastema. 



2. When fully formed, they are regularly-organized anatomical elements, subject to 

 the same laws of gradual molecular waste and repair as any of the anatomical elements 

 of the tissues. 



3. They are generated de novo in the adult, when diminished in quantity by haemor- 

 rhage or otherwise ; and, under these circumstances, they are probably formed in the 

 liquor sanguinis, by the same process by which they take their origin in the ovum. 



Function of the Blood-Corpuscles. Although the albuminoid constituents of the plasma 

 of the blood are essential to nutrition, the red corpuscles are the parts most immediately 

 necessary to life. We have already seen, in treating of transfusion, that life may be re- 

 stored to an animal in which the functions have been suspended from haemorrhage, by the 

 introduction of fresh blood ; and, while it is not necessary that this blood should contain 

 the elements of fibrin, it has been shown by the experiments of Prevost and Dumas and 

 others, that the introduction of serum, without the corpuscles, has no restorative effect. 

 When all the arteries leading to a part are tied, the tissues lose their properties of con- 

 tractility, sensibility, etc., which may be restored, however, by supplying it again with 

 the vivifying fluid. We shall see, when we come to treat of the function of respiration, 

 that one great distinction between the corpuscular and fluid elements of the blood is the 

 great capacity which the former have for absorbing gases. Direct observations have 

 shown that blood will absorb from ten to thirteen times as much oxygen as an equal bulk 

 of water ; and this is dependent almost entirely on the presence of the red corpuscles. As 

 all the tissues are constantly absorbing oxygen and giving off carbonic acid, a very im- 

 portant function of the corpuscles is to carry oxygen to all parts of the body. In the 

 present state of our knowledge, this is the only well-defined function which can be 

 attributed to the red corpuscles, and it undoubtedly is the principal one. They have an 

 affinity, though not so great, for carbonic acid, which, after the blood has circulated in 

 the capillaries of the system, takes the place ot the oxygen. In some experiments per- 

 formed a few years ago on the effects of haemorrhage and the seat of the " besoin de re- 

 apirer" we demonstrated that one of the results of removal of blood from the system 

 was a condition of asphyxia, dependent upon the absence of these respiratory elements. 



Leucocytes, or White Corpuscles of the Blood. In addition to the red corpuscles of 

 the blood, this fluid always contains a number of colorless bodies, globular in form, in the 

 substance of which are embedded a greater or less number of minute granules. These 

 have been called by Robin, leucocytes. This name seems more appropriate than that ot 

 white or colorless blood-corpuscles, inasmuch as they are not peculiar to the blood, but 

 are found in the lymph, chyle, pus, and various other fluids, in which they were formerly 

 known by different names. All who have been in the habit of examining the animal 

 fluids microscopically have noticed the great similarity between the corpuscular elements 

 found in the above-mentioned situations ; and, as microscopes have been improved and 

 investigations have become more exact, the varieties of corpuscles have been narrowed 

 down. It is now pretty generally acknowledged that the corpuscles found in mucus and 

 pus are identical ; also, that there is no difference between the white corpuscles found in 



