•THEAlCroi&COPE- 



NEW YOR 



BOTANJCA 



QARjDOM 





Vol. XI. 



TRENTON, N. J., JANUARY, 1891 . 



No. 1. 



ORIGIMAL 



ConnvMiCATions 



THE COLORLESS CELLS OF THE BLOOD. 



GEORGE A. PIERSOL, M. D., 



I'ROFESSOR OF HISTOLOGY AND EMBRYOLOGY IN THE UNIVERSITY OF 



PENNSYLVANIA. 



THE little nucleated naked and colorless masses of active pro- 

 toplasm observed among the colored cells in the blood are 

 elements having a very wide distribution, being constant among 

 the vertebrates, and occurring in the circulating fluid in many of 

 the lower animals. 



The colorless or " white " blood corpuscles represent the type 

 of the embryonal cell, and exhibit in a high degree the charac- 

 teristics of free, active, formative protoplasm, such as in the 

 early stages of the animal constituted its greater part. In com- 

 mon with all other free masses of active protoplasm, these cells 

 continually exhibit marked alterations in form, and since such 

 changes closely resemble those observed in that simple animal, 

 the Amceba, they were, naturally enough, termed " amoeboid," 

 and while, of course, not identical, the Amceba and the colorless 

 blood cell both possess this characteristic of active protoplasm, 

 the substance of which both are formed. 



