2iO DR. BEALE, ON THE TISSUES, 



to consist of a membrane with certain fluid coloured contents. 

 A nucleus is to be demonstrated in some, although not in the 

 adult human blood-corpuscle. The opinion generally received 

 is certainly that the human red blood-corpuscle is a cell with 

 red contents, the nucleus of which has disappeared, or else 

 it is the free nucleus of a cell, — and here the question is dis- 

 missed. 



But the blood-corpuscle may also be regarded as a cor- 

 puscle consisting of matter of different density in different 

 parts, being firm externally, but gradually becoming softer, 

 so as to approach to the consistence of fluid towards the 

 centre. Dr. Dalton, of New York, has expressed this opinion 

 of the structure of the blood-corpuscle in his published lec- 

 tures, and some few other observers entertain similar views. 



Dr. Beale had never succeeded in seeing the cell-wall said 

 to exist, neither had he been able to confirm the oft- repeated 

 assertions with regard to the passage of liquid into the in- 

 terior of the corpuscle by endosmose, its bursting, and the 

 escape of its contents through the ruptured cell-wall. When 

 placed in some liquids, many of the corpuscles Swell up and 

 disappear, but the ruptured cell-walls could not be discerned. 

 The red blood-corpuscles from the same animal differ in 

 character in a much greater degree than observers generally 

 seemed disposed to admit. Some are darker and harder than 

 others. Some are so transparent as to be invisible without 

 the greatest care, and corpuscles may be found which are 

 not more than the fifth or sixth of the size of an ordinary 

 blood-corpuscle. The lecturer had failed in his attempts to 

 colour the red blood-corpuscles drawn from capillaries or from 

 a vein, with carmine, but he had succeeded in colouring many 

 in clots taken from the vessels after death ; and, in some 

 instances, certain of the corpuscles within the capillaries of 

 a stained tissue have been coloured. These corpuscles were 

 very much smaller than the white corpuscles, which are 

 always very readily coloured, and did not exhibit the well- 

 known granular appearance characteristic of the latter. It was, 

 therefore, inferred that they were young, red blood-corpuscles. 



The majority of the red blood-corpuscles of the human sub- 

 ject are certainly not to be coloured by carmine, the same pro- 

 cess being employed as that by which the white corpuscles are 

 always so readily coloured. The granular or nucleated corpus- 

 cles of the embryo are readily coloured. The nuclei of the cor- 

 puscles of the frog become coloured, but the external portion 

 which is coloured naturally is not tinged by carmine. In winter 

 the capillariesof the frog contain numerous oval corpuscles, sur- 

 rounded by a very thin layer of the external coloured portion. 



