DIGESTIVE ACTIVITY OF MESENCHYME. 103 



swollen. Only few mesenchymal cells are found in direct con- 

 tact with the edestin particles fifteen minutes after the injection, 

 hut even at that time these cells, if compared with those situated 

 at a distance from the injected material, seem to be larger, their 

 processes shorter and plumper and their cytoplasm often filled with 

 tiny vacuoles giving it a foamy appearance. There is no doubt 

 but that these changes in the mesenchymal cells, observed almost 

 immediately after the injection, are not to be regarded as a specific 

 response to the introduction of the edestin. Practically the same 

 changes are seen after an injury produced by the introduction of 

 the glass pipette without injection. 



A breaking off of the syncytial arrangement of the cells and 

 formation of typical wandering cells can be observed in those few 

 mesenchymal cells which are in close proximity to the injured 

 tissue. The number of wandering cells formed in loco at the 

 expense of the mesenchymal cells is small indeed, the mesen- 

 chymal cells themselves being scarce. These local changes are 

 slow and are quickly overshadowed by the appearance of cellular 

 elements brought in by the blood stream. 



Effect Produced by flic Presence of the Injected Substance. 

 The changes observed in the region in which the injected masses 

 are situated and dependent upon their presence are in part identical 

 to those found, if only injury with the glass pipette were produced 

 and the injection omitted. They differ greatly, however, in their 

 intensity and in their duration. In describing the changes ob- 

 served around and within the injected mass, three different phases 

 will be reported under separate sections, (i) Appearance of 

 wandering cells. (2) Digestive processes. (3) Phagocytes after 

 digestion. 



i. Appearance of Wandering Cells. As mentioned above, ves- 

 sels are seldom ruptured during injection and only a few groups 

 of extravasated blood cells are found around the injected mate- 

 rial. Among those the white blood corpuscles are seen to exhibit 

 an intensive activity, the erythrocytes, however, lie inert in the 

 intercellular spaces at first. Shortly after the injection the white 

 blood corpuscles become greatly increased in numbers around the 

 injected masses. Not only in nearest proximity but also at a cer- 



