154 CIRCULATING FLUIDS: 



is formed, but there is no doubt that the respiratory process is 

 essential to its production. 



Schultz and Henle have examined the blood-corpuscles in 

 their various stages of development, and have arrived at very 

 similar conclusions. Schultz' observed that the young corpus- 

 cles were poorer in colouring matter than the older ones, and 

 that, consequently, the nucleus was much more distinct. The 

 capsule becomes tumid in proportion to the age and development 

 of the blood-corpuscle, whilst the nucleus becomes gradually 

 smaller, and in some cases entirely disappears. Water acts very 

 differently on blood-corpuscles in different stages of develop- 

 ment. The younger and more delicate blood-corpuscles are 

 quickly and readily dilated by a very small quantity of water ; 

 they are soon entirely deprived of their colouring matter, and 

 become perfectly clear and transparent ; whilst the older and 

 more developed corpuscles entirely resist the action of water, or 

 at the most only become rounded, and do not dissolve except 

 on the addition of a large quantity of water. They remarked 

 at the same time that the corpuscles most abundant in colour- 

 ing matter frequently presented a minute nucleus up to their 

 final disappearance ; while many of the most highly developed 

 ones gave no indications whatever of a nucleus. 



That a metamorphosis of the blood-corpuscles does occur can- 

 not be for a moment doubted, but with respect to the peculiar 

 circumstances under which it is conducted, and to the products 

 that are then formed, we know scarcely anything : all that we 

 have been able to ascertain with any degree of certainty is, that 

 oxygen is absorbed, and carbon given off during the process; 

 and the following facts justify us in this conclusion : 



a. Dark blood, both within the system and out of it, as- 

 sumes a lively reddish tint on being brought in contact with 

 oxygen. This change is probably based on a chemical change 

 in the hsematin. 



h. Blood taken from the body and agitated with oxygen 

 absorbs a certain portion of the gas, while carbonic acid is 

 formed. The mere serum, however, which contains no blood- 

 corpuscles, absorbs only a very little oxygen, and develops car- 

 bonic acid in a corresponding ratio. 



' Ueber die gehemmte und gesteigerte Auflosung und Ausscheidung der verbrauch- 

 teu Bliitblaschen. Hufelaiid's Journal, 1838. 



