IO2 VERA DANCHAKOFF AND S. M. SEIDLIN. 



tissue. A continuous layer of mesenchymal cells is situated di- 

 rectly under the basal membrane of the epidermis. These cells, 

 as well as those situated within the plate itself, are typical loose 

 connective tissue cells with numerous long" cytoplasmic processes, 

 with oval nuclei usually containing well-defined nucleoli and minute 

 particles of chromatin. Occasional mitoses are found among 

 them. Chromatophores are few in this tissue, but are not in- 

 frequently found surrounding the vessels and accompanying even 

 tiny vascular branches. 



Results of the Experiments, 



In describing and analyzing the various phases of the reaction 

 developed around the injected material, a distinction has to be 

 made between the processes due to the injury proper and those 

 which develop in consequence of the presence of foreign matter, 

 digestible particulars protein in this case. The reaction due to 

 the injury is exhibited partly by local cells, partly by elements 

 brought in by the blood current from remote parts of the organ- 

 ism. The reaction due to the injury is, in these experiments, only 

 slight in both of these aspects and is greatly overshadowed, 

 shortly after the injection, by processes depending upon the pres- 

 ence of the injected material. 



Effect Produced by tJie Injury during Injection. Besides a 

 slight injury of the epidermis, a few cells of which are sometimes 

 carried into the mesenchymal plate, the direct consequence of the 

 injection is the boring of a canal in the midst of the loose mesen- 

 chymal tissue and the filling of it by finely pulverized proteinic 

 matter. It is remarkable how seldom appreciable hemorrhages are 

 produced, and only very few blood corpuscles are regularly found 

 free in the intercellular spaces as a result of the puncture of a few 

 small vessels. By pushing the glass capillary under the epidermis 

 the tissue is simply compressed, this compression being further 

 exercised by the thick suspension of edestin after the withdrawal 

 of the glass capillary. Microscopically the injected material ap- 

 pears in the form of a rather sharply defined strand of densely 

 aggregated particles. The immediately adjacent tissue becomes 

 slightly edematous and the white fibers traversing the fin plate 



