432 ELIOT R. CLARK AND ELEANOR LINTON CLARK 



contained, the larger of which were refractile and indistinguish- 

 able from the droplets composing the emulsion. 



When continuous observations of the injected region were 

 made together with records drawn at five to ten minute inter- 

 vals, it was found that pigmented leucocytes migrated from the 

 injected mass and approached the tip or wall of a nearby lym- 

 phatic capillary. Here they remained for from five to ten min- 

 utes closely adherent to the lymphatic and then moved away. 

 Just before or at the time of wandering away again, the leu- 

 cocytes lost their pigment and, in most cases, became quite 

 clear (fig. 8). This reaction of the pigmented leucocytes to 

 lymphatics was similar to that described for the other two in- 

 jected substances, but here the process was completed in a 

 shorter time than in the case of the oleic acid and much more 

 rapidly than in the case of the olive oil. In those larvae in 

 which the yolk of egg or cream had been introduced near a 

 lymph capillary, leucocytes containing granules and droplets 

 approached the lymphatics within two or three hours following 

 an injection. When the substance was injected at some dis- 

 tance from a lymph vessel, the pigmented leucocytes remained 

 in a thick cluster at the injection site for ten to twenty-four 

 hours and then many of them wandered away, often moving 

 toward a growing lymphatic sprout. In such cases, most of the 

 leucocytes lost their pigment before coming in contact with a 

 lymphatic capillary. 



The absorption of cream and of yolk of egg took place 

 extremely rapidly: twelve hours after the injection, most of the 

 droplets had been taken up by leucocytes and at the end of 

 twenty-four hours, all of them had been. On the second day 

 after the injection, only a few pigmented leucocytes were pres- 

 ent at the point of the injection (figs. 5 and 9). 



On account of the rapidity of the absorption, the response of 

 lymphatics toward the injected cream or yolk was not so strik- 

 ing as in the case of the substances which were absorbed more 

 slowly, since in many cases, the leucocytes had taken up all of 

 the fat droplets and many of them had started to migrate 

 toward the lymphatics before there was time for any marked 



