180 VICTOR E. EMMEL 



b. In other vertebrates 



As is well known, the definitive red blood corpuscles of the lower 

 vertebrates in contrast to that of adult mammals are typically 

 nucleated cells. On the other hand, it appears that non-nucleated 

 erythrocytes are normally present even in the blood of some of 

 these lower forms and furthermore that these elements may play 

 a role in respiratory functions. The following observations con- 

 cerning the origin of these non-nucleated elements are of especial 

 interest with relation to our present subject. 



Giglio-Tos ('97) described for the blood of the Lamprey the 

 division of the red blood cells into nucleated and non-nucleated 

 parts, and designated the process as one of 'merotomie.' He 

 regarded the process as a purely physical one which, however, 

 he concluded had the important function of increasing the sur- 

 faces concerned in gaseous exchange. In 1899 Giglio-Tos was 

 also able to confirm Eisen's ('97) earlier observation of the oc- 

 currence of a similar process in Batrachoseps attenuatus, con- 

 cerning which he states his opinion that these non-nucleated 

 elements take part in respiratory function as well as the nucleated 

 erythrocyte. For triton. Jolly ('04) describes a process of cytoplas- 

 mic constriction in the erythrocytes referring to which in his re- 

 cent work ('07) on erythrocytes, he says: 



J'ai montre (1904) que, chez le Triton, au moment de la regeneratton 

 du sang apres le jeune, le protoplasme de beaucoup de globules prets a 

 la division forme un gros bourgeon pediculise se separant du fragment 

 contenant le noyau. Non seulement on trouve tous le stades de cette 

 transformation, mois on voit dans la preparation, quelquefois nombreux, 

 fibres au milieu des cellules, ces gros fragments protoplasmiques spheri- 

 ques et san noyau (p. 195). 



which as he states is not to be regarded as due to artificial condi- 

 tionsi. Jolly ('04) referring to Giglio-Tos' observations remarked 

 that: 



En presence de ce phenomene, tres distinct de la denucleation, ex- 

 pulsion du noyau, on ne peut s'empecher de penser immediatement au 

 bourgeonnement protoplasmique des cellules de Neumann, bourgeonne- 

 ment decouvert par Malassez, en 1882, dans la moelle des jeunes Mam- 

 miferes, et qui pour lui est 1' origine des globules rouges sans noyau, 



