DIGESTIVE ACTIVITY OF MESENCHYME. 115 



est part of the phagocytes are seen to leave the region and settle 

 in new places. 



The phagocytes are seen to be very active in leaving the region 

 of the injection as soon as they have completed the digestion of 

 the ingested particles. The large aggregations of these cells are 

 being dispersed, and 4 days after injection the egress of phagocytes 

 is very intensive. At this time lymphoid phagocytes can be de- 

 tected at a good distance from their previous location. Small 

 groups of phagocytes are gathered directly under the epidermis. 

 Two or three weeks after injection they can still be recognized as 

 cell units with definite structure. What is even more remarkable 

 is, that the cells are seen not infrequently to undergo mitosis. 



Though on the basis of the present experiments a complete 

 description of the distribution of the phagocytes cannot be given, 

 there are undoubtful indications that their new whereabouts are 

 not confined to the tadpole tail. The phagocytes, while moving 

 from the region of injection, come not infrequently across vessels. 

 Vessels have grown by this time also into the injected region, and 

 numerous phagocytes are now seen to be directly applied against 

 the thin-walled vessels. It is also possible to detect some of these 

 phagocytes within the vessels. It is natural that such pictures 

 are extremely rare, because the phagocytes, once entered into a 

 vessel, are promptly carried away. 



The uninterrupted egress of the phagocytes reduces the wide 

 strands of densely accumulated phagocytes to a hardly visible 

 scar (Fig. 5). The cells in it are of two kinds: Typical mesen- 

 chymal cells and typical histiotopic or resting wandering cells. 

 The latter are the less numerous. As compared with Figure 4, 

 Figure 5 shows that the egress of the phagocytes is chiefly re- 

 sponsible for the loosening of the tissue and for the shrinking of 

 the previously wide strand of the densely infiltrated region. 



CONCLUSIONS. 



The introduction of a large amount of edestin into the mesen- 

 chymal plate of the tail of the tadpole produces a local and a 

 general reaction in the organism. The local reaction consists in a 

 response of mobile and mobilisable cells and results in a dense 

 infiltration of the injected mass with consecutive ingestion and 



