IO4 VERA DANCHAKOFF AND S. M. SEIDLIN. 



tain distance there appear a great number of ameboid cells. The 

 granular leucocytes are the earliest to come and during the first 

 hours after injection they are found to be the most numerous. 

 Their structure allows of an easy identification, their polymorphic 

 nucleus being especially characteristic. Most of the leucocytes 

 belong to the neutrophil class. Present in large numbers within 

 the vessels, they are first to emigrate and to appear around the 

 injected masses. Within the vessels and in close proximity to 

 them they present the usual structure, but soon undergo consider- 

 able changes in their appearance. Their nuclei are often drawn 

 lengthwise and appear in a thread-like shape. The chromatin in 

 the nucleus is also arranged in the form of rod-like particles. 

 This is of course due to intensive streaming movements exhibited 

 by these cells. But a more substantial change takes place in their 

 cytoplasm. This greatly increases in volume and though still 

 granular is much less distinctly so. 



In addition to the granular leucocytes, a number of ameboid 

 cells with round nuclei appear soon. Twelve to fourteen hours 

 after the injection they greatly increase in number and after 

 twenty-four hours they are by far the most numerous among the 

 cells infiltrating the region. These ameboid cells, which become 

 most active in the process of digestion of the injected protein, 

 exhibit the structure characteristic of the small lymphocytes. It 

 is only after a thorough investigation that this conclusion has 

 been reached. A few hours after injection when numerous poly- 

 morphonuclear leucocytes have already emigrated, the vessels 

 throughout the tadpole and especially those in proximity to the 

 injection begin to show an increasing number of small lympho- 

 cytes. The characteristic structure, which enables an easy recog- 

 nition of these cells within the vessels, is also present even to 

 minute details in cells which have recently emigrated and are situ- 

 ated near the injected substance. Small in size, they have a round 

 nucleus containing numerous well-defined chromatin particles and 

 no nucleoli. The nuclear membrane is chromatic and sharply de- 

 fined. The cytoplasm is slightly basophilic and appears in the 

 form of a narrow rim. Outside the vessels they exhibit numerous 

 ameboid processes. 



