712 SPECIAL HISTOLOGY. 



diversely bent and plicated discs. All concentrated solutions of metallic 

 and other salts, act in the same way, unless, like nitrate of silver, they 

 exert an immediately destructive influence. Donders and Moleschott 

 have carefully investigated the reactions, especially of such soluble 

 salts as exist in the blood, and have found that a concentrated solution 

 (1 part salt, 7 parts water) added to an equal volume of blood, dimi- 

 nishes all the cells, and reddens the blood. The cells are least affected 

 by the hydrochlorates of soda and potassa, much more by the phosphate 

 and carbonate of soda, and nitrate of potassa, most of all by the sul- 

 phates of soda and potassa. When diluted (1 part salt, 17 parts water), 

 all these salts color the blood a dark wine-red, and produce a distension 

 of the cells, rendering them pale, and completely dissolving them at the 

 end of four or five hours; in this regard the soda-compounds, except 

 common salt, which exerts no destructive action, prove more energetic 

 than those of potassa. I find changes similar to those caused by the 

 salts, to take place on the addition of alcohol, tincture of iodine., chromic 

 acid, and creasote, the first two of which merely render the blood-globules 

 smaller and corrugated, the latter also causing them to become granular 

 internally. In this respect the action of creasote is the most remark- 

 able, which transforms the blood-corpuscles partly into perfectly opaque, 

 even fat-like glistening granular and homogeneous granules and globules, 

 and partly into very beautiful clear vesicles, which may even be ren- 

 dered polygonal by their mutual pressure. Lastly, it is very important 

 to notice the influence of oxygen and of carbonic acid on the blood, 

 which by their reception into the interior of the cells, both in the body 

 (in the pulmonary and systemic capillaries) as well as externally to it, 

 as proved by experiment, produce sometimes a brighter, sometimes a 

 darker color in it. This takes place without any change of form in the 

 blood-corpuscles (J. MUller, and Todd and Bowman, in opposition to 

 Nasse and Harless), and the experiment may be alternately made several 

 times in succession with the same blood without any alteration of the 

 corpuscles (Magnus, Bischoff, Del'Espinasse, and Renemann, in opposi- 

 tion to Harless). Those gases also act upon the coloring matter of the 

 blood, when isolated, in the same way as upon the corpuscles (Magnus, 

 Marchand), and it is probable that the change of color is not connected 

 with any chemical change in the hcematin, but is a physical action of a 

 peculiar kind, analogous to similar changes of color in other fluids 

 caused by the absorption of gases. 



Blood-corpuscles of other animals. — The non-nucleated blood-corpus- 

 cles of the Mammalia do not differ in form from those of Man, except 

 that in the Camel and Llama [Aiichenia Paco, A. Crlama, A. Vicugna) 

 they are oval, and 0-0038 of a line long ; they are mostly smaller than 

 in Man, as in the Dog, 0-0031, Babbit, Rat, 0-0028, Swine, 0-0027, 

 Horse and Ox, 0-0025, Cat, 0-0024, Sheep, 0-0022 of a line, the small- 



