82 ABSORPTION AND EXHALATION. L,ECT. IV. 



tion was introduced into the body of the frog simply by 

 imbibition ; and this phenomenon, being effected in the 

 living as well as in the dead frog, certainly cannot be re- 

 garded as different from the imbibition which we have 

 already studied, which belongs to both organic and in- 

 organic bodies, and which is the consequence of their 

 cellular and vascular structure, &c. 



But there is something more than this. In the heart and 

 lungs of a living freg we find a much larger quantity of the 

 absorbed solution than in the other parts of the body, 

 although these latter were much nearer the part immersed. 

 These viscera are the centre of the circulatory system : in 

 them commence or terminate the trunks of the blood-vessels. 

 The solution of the ferrocyanide, therefore, has penetrated 

 the blood-vessels by imbibition, mingled with the blood, 

 and thus arrived at the heart and lungs. 



We have another very simple experiment proving the 

 same facts : I take two frogs, and from one remove the 

 heart ; the animals are equally lively. Both are placed in a 

 large glass containing a solution of the extract of nux vomica. 

 The animal with the heart is soon poisoned, and long before 

 the other becomes affected. 



Jill Vessels absorb. It has for some time been a subject 

 of discussion whether the lymphatic vessels or the veins 

 were exclusively endowed with the power of absorption : 

 that is, whether a substance could be directly introduced 

 into the blood-vessels by passing through the tissue of their 

 sides ; or whether it must necessarily first pass through the 

 lymphatics. As every part of an organized being more or 

 less easily imbibes water, saline solutions and serum, it is 

 clear that the first part of absorption may take place through 

 the sides of the lymphatics, as well also as through those of 

 the blood-vessels. Microscopic anatomy, by unveiling the 

 manner in which the blood-vessels and lymphatics terminate, 



