THE BLOOD AND THE LYMPH. 333 



circumstance that older cells usually have firmer membranes 

 than younger ones, and also that blood -corpuscles, left to their 

 fate out of the circulation — for instance in extravasated blood — 

 always, in time, become more resistant -, but it must be allowed 

 that, at present, no decisive opinion can be given either way. 

 Many other substances act in the same manner as water, only 

 more powerfully and even destructively, particularly acids and 

 alkalies; although not all with equal energy. Gallic and 

 pyroligneous acids, aqueous solutions of chlorine and iodine, 

 sulphuric ether and chloroform, act very much in the same 

 way as water. In the first three the blood-globules remain as 

 distinct, pale rings, whilst in sulphuric ether they are instan- 

 taneously transformed into the most delicate and excessively 

 faint rings, \ — \ the original size, and which it is very diffi- 

 cult to perceive in the finely granular coagulum that is formed 

 at the same time, although they are rendered more distinct by 

 the addition of salts (nitre for instance) . I have seen no evi- 

 dence of an actual solution of the cells. Chloroform acts in 

 the same manner, only more slowly, and the corpuscles first be- 

 come considerably smaller, and of a glistening yellow colour. 

 Acetic acid, of 10£, at once renders the corpuscles extremely 

 faint, so as to be scarcely perceptible, but they are by no 

 means dissolved, being visible, even at the end of several hours, 

 in the form of delicate rings. A solution, containing 20 per 

 cent, of acid, acts more energetically, and in glacial acetic 

 acid, the cells are completely dissolved in the space of two 

 hours, in the slimy brown blood. Concentrated sulphuric acid 

 renders the blood black-brown. The corpuscles become pale, 

 and although still retaining some colour, are scarcely recog- 

 nisable, their contours running mutually together. On the 

 addition of nitre or water, which latter throws down a white 

 precipitate, they again become distinct as minute, dull-yellow, 

 round corpuscles. After some hours' action of the acid all is 

 dissolved. Concentrated hydrochloric acid, which colours the 

 blood brown, and produces a white precipitate, contracts most 

 of the cells, which are gradually dissolved, and renders many 

 of them granular internally, also producing rents in some 

 of them, so that the contents escape, in the form of a pale 

 streak, appearing like a stalk to the corpuscle ; subsequently they 

 become so faint in colour as to be scarcely perceptible, without 



