446 ELIOT R. CLARK AND ELEANOR LINTON CLARK 



proteolytic ferment. It is justifiable to conclude from all of 

 the foregoing observations that leucocytes play some part in the 

 absorption of fat. 



The observations reported at this time, on the reaction of liv- 

 ing cells to fat injected subcutaneously, showed that leucocytes 

 are strongly attracted toward the various fatty substances se- 

 lected for these experiments, that they phagocytose the fat and 

 usually convey the engulfed fat to a nearby lymphatic, and that 

 they transform the fat intracellularly into a soluble substance or 

 substances which are absorbed by the lymphatic. The chemical 

 constitution of the products of this lipolysis obviously could not 

 be determined by the present method of study. And it is, of 

 course, impossible to state how far the results of these obser- 

 vations are applicable to the question of fat absorption in the 

 intestine. 



Another point which came out strikingly in the present ex- 

 periments is that the rate of absorption of fat injected subcu- 

 taneously is dependent upon its physical state, that finely di- 

 vided emulsions are taken up and disposed of much more quickly 

 than those substances which exist as single globules of oil. 



The very rapid transformation of oleic acid immediately after 

 its injection into what was probably sodium oleate has been 

 described. Just what element in the tissue fluid caused this 

 reaction cannot be stated. We also are not prepared to ex- 

 plain the nature of the small refractile droplets which made their 

 appearance through and around the opaque mass of soap on the 

 day following the injection. Frank and Ritter (11) have shown 

 that carbon dioxide wdll cause the splitting of fatty acid from 

 soap, in vitro, and perhaps this may be the explanation of this 

 phenomenon. 



SUMMARY OF RESULTS 



a. Lymphatic endothelium, in the tail of the frog larva, reacts 

 positively toward the fatty substances, olive oil, oleic acid, cream 

 and yolk of egg, injected nto the tissue spaces, by sending out 

 sprouts which grow to or toward them. 



