426 ELIOT R. CLARK AND ELEANOR LINTON CLARK 



became ]:)ig;inented. This pigment consisted of numerous small 

 brown granules, the larger of which - looked clear and refractile 

 by transmitted light and were apparently small drops of oil. 



When this region was observed and drawn at intervals of a 

 few hours, it was obvious that lymphatic capillaries were at- 

 tracted by the presence of the oil. A branch from a nearby 

 lymph vessel, soon showed a tendency to grow in the direction 

 of the globule, even bending out of its course to do so, and 

 reached the rim of pigmented leucocytes within a few hours, or 

 after two or three days, depending upon its distance from the 

 globule at the time of injection. After reaching the oil, the tip 

 of the lymphatic remained in close contact with the encircling 

 leucocytes for several days. Occasionally, the tip of the Ij^mph 

 sprout later extended beyond the oil, and in such instances the 

 wall of the lymphatic remained in close proximity to the pig- 

 mented leucocytes and to the globule. No pigmented leucocytes 

 were seen to enter a lymphatic. 



The exact relationship of the lymphatics to the oil and its 

 rim of leucocytes was often difficult to determine. In other cases, 

 such as the one illustrated in figure 6, the peculiar relationship 

 could be observed to better advantage. In such an instance, a 

 leucocyte containing oil droplets of varying sizes could be seen, 

 closely adherent to the tip or wall of the lymphatic capillary 

 which had grown out to the globule. Often a leucocyte remained 

 in such a position with relation to the lymphatic for as long as 

 six to eight hours and, during this period, the larger oil drops 

 gradually became smaller and finally thB very small droplets 

 and granules decreased in amount and the leucocyte became 

 clear. The process was more readily understood after watch- 

 ing a similar occurrence in the case of the other injected sub- 

 stances, where the reaction takes place more rapidly, and will 

 be described in greater detail in that connection. 



A number of times during the period of two to three weeks 

 in which the absorption of injected olive oil was observed, small 

 globules about one-tenth to one-fifth the size of the main globule 

 became separated from the rest of the oil. These smaller glob- 

 ules were engulfed by leucocytes, although in many cases they 



