SECT. 221.] BLOOD-CORPUSCLES IN ANIMALS. 



5^5 



Fig. 213. 



When diluted, such salts cause the blood-cells to swell up ; and the same 

 effect is sometimes produced by concentrated solutions also. — Lastly, we 

 have to mention the very important influences of oxygen and carbonic acid 

 upon the blood-cells, the absorption of which gases, into the interior of the 

 deSj both in the living subject (in the lungs and systemic capil- 

 laries) and in experiments out of the body, is the cause of the different hues 

 exhibited by the blood. This absorption takes place without altering the 

 form of the cells, and the two gases may be applied alternately several times 

 over to the same specimen of blood, without altering the blood-corpuscles in 

 any manner. The gases in question also act in a similar manner upon the 

 isolated colouring mutter of the blood as upon the blood-corpuscles {Magnus, 

 Marchand), and even upon the red blood-crystals. The researches of Schon- 

 h in and His, which show that the contents of the blood-cells have the power 

 of changing oxygen into ozone, afford us a hope that these important re- 

 lations may soon be better understood than has been possible hitherto. 



Blood-corpuscles of other Animals. — The non-nucleated blood-corpuscles of 

 mammalia do not differ in form from those of man, except that those of the 

 camel and llama are oval, and 0*0038'" long ; they are mostly smaller than in 

 man, measuring in the dog 0*003 1'"; in the rabbit and rat, 0-0028'"; pig, 

 0-0027'"; horse and ox, o , oo25'"; cat, 0-0024'"; sheep, 0-0022'". They are 

 smallest in the musk deer (0-00094."'), and only in a few instances are they 

 larger than in man ; thus in the elephant they measure 0-005"'. — All the lower 

 classes of vertebrata have almost invariably oval nucleated blood-corpuscles 

 of the form of pumpkin-seeds. Those of birds are 

 as much as 0-004'" to o - oo8'" in length, and have 

 rather roundish nuclei ; those of amphibia measure 

 between 0-008'" to 0-025"' m length, and have either 

 round or oval nuclei. The blood-cells are largest in 

 the naked amphibia, measuring in the frog, o-on'" to 

 0-013'" in length, o'oo/"' to o - oo8"' in breadth; in the 

 proteus, 0-025'" m length, o - ooi6"' in breadth ; and in 

 •the salamander, 0-02'" in length : those of fish, lastly, 

 generally measure 0-005'" to 0-007'" m length, except 

 those of the plagiostoma, which reach to o-oi'" to 

 0-015'", and those of the lepido-siren, 0-020'" in length, 

 o-oi2'"in breadth. Those of myxine and petromyzon 

 are 0-005'" i u diameter, round and slightly bi-concave. 

 Leptocephalus has colourless blood-corpuscles, and 

 amphioxus none whatever. — The blood-corpuscles of the invertebrate/, resem- 

 ble the colourless cells of the blood of the higher animals, and are almost 

 always uncoloured. 



As extraordinary constituents of the blood we still have to mention here the 

 following : 1, cells, inclosing blood-corpuscles, observed by Eckcr and myself 

 in the blood of the spleen and hepatic vessels, and also elsewhere in the 

 blood (see my Micr. Anat. ii, 2, p. 269, et scq.); 2, pigment-cells and colour- 

 Its* granular cells, observed by myself, Eclter, Meckel, Virchow, and Fuuke, 

 especially in intermittent fevers, and in affections of the spleen ; 3, peculiar 

 concentric bodies, three or four times the size of the colourless blood-cor- 

 puscles, and similar to those of the thymus (see Henle, Zeitschrvftf.rat. 

 Path., bd. vii., p. 44.), found by Wassail in fibrinous coagula of the heart ; 



1. Blood-cells of the 

 frog. a. seen from the 

 surface ; 6. from the 

 side ; c. decolourised 

 by water. 2. Blood- 

 cells of the pigeon, a. 

 seen from the surface ; 

 b. from the side. 



