404 THE BLOOD, BY ALEXANDER ROLLETT. 



action produced by the exposure of the blood corpuscles of the 

 newt and frog alternately to carbonic acid and air. 



So long as the blood remained unchanged he observed only 

 the already-mentioned phenomena in the micro-spectrum, and 

 was thus enabled to correct the older inexact statements.* 

 Blood corpuscles changed by the action of water, however 

 behaved themselves differently. 



Strieker applied water in the form of vapour, by which 

 means very fine gradations in the amount supplied can be 

 attained. 



On transmitting carbonic acid he then observed the occur- 

 rence of precipitates both in the nucleus and in the substance 

 of the corpuscle ; these precipitates vanished with oxygen, and 

 returned with carbonic acid, and so on. Strieker considers these 

 appearances, as had already been held by A. Schmidt and 

 Schweigger-Seidel in the case of the precipitate obtained by 

 the action of carbonic acid in the ' substance of the blood 

 corpuscles of the frog, to be caused by the separation of para- 

 globulin; in order, however, to obtain such precipitates the 

 addition of water must be carried almost to the extent of 

 rendering the blood corpuscles colourless. 



If smaller quantities of water be added, these precipitates do 

 not occur. Under certain conditions the remarkable form 

 appears that we have already described (fig. 73, a). This form, 

 as an easily repeated experiment of Strieker shows, vanishes 

 with an excess of carbonic acid. The blood corpuscles then 

 appear once more equably tinted, and on the admission of air 

 revert again to their original form. 



With the addition of a certain amount of water the nucleus 

 alone becomes tuberculated, and more sharply defined when 

 carbonic acid is transmitted, whilst upon the passage of air 

 it again becomes smooth. If this stage be exactly attained, 

 the whole blood corpuscle may be seen to become spherical 

 with carbonic acid, and again to assume its smooth form on the 

 admission of air. Moreover, the thorn-apple form of the 

 mammalian blood corpuscles can be made to disappear by car- 



\ Harless, Monographie uber den Einfluss derGase auf die Form. Erlangen 

 1846. " Monograph on the influence of gases on form." 



