43 



Their role in the metabolic processes has doubtlessly been 

 exagerated, especially by Cuenot 23) who assumed that they 

 take care of the transportation of the food to the tissues. 

 Chapeaux 15) also has exagerated their role in the assimilation 

 of fat ; his hypothesis that fat would be infiltrated by the gut- 

 epithelium, passed unchanged, given off to the coelomic liquid 

 and be digested there by the corpuscles, will be discussed in 

 the next chapters. They doubtlessly contain enzymes ; see chapter 

 14. But this is the case just as well with mammalian leucocytes. 

 M tiller and Jachmann (Munch, med. Wochenschr. 1906. 

 1393, 1507 and 2002) demonstrated the presence of a proteolytic 

 enzyme in leucocytes; Haberlandt (Pfliiger's Arch. 132. 1910. 

 175) and Mancini (Biochemische Zschr. 26. 1910. 140) found 

 a diastase. 



All data concerning movements of the corpuscles unanimously 

 prove that they only move from inside to outside (see chapter 3). 

 I myself never succeeded in finding any amibocytes in the gut- 

 contents samples studied for the experiments in chapter 9 etc. 

 From such considerations it is not probable that the amibocytes 

 would participate to any extent in the transportation of food ; 

 on the contrary, their life-circle goes the inverse way ; born in 

 the lymph-glands they pass into the coelomic fluid and leave 

 the body by different ways (see the chapter on excretion) loaded 

 with waste. 



Possibly they also play a role as store of reserve substances 

 (Cuenot). Echinochrome and other fats are found in them, the 

 protein-crystalloids will be discussed in chapter 25. I can not 

 concieve however how the two functions of excretion and 

 storing of reserves can be located in the same organ however. 



16. THE DIGESTION AND UTILISATION OF FATTY 

 SUBSTANCES. EMULSIFYING ENZYMES? 



The digestion of fats is one of the most difficult and obscure 

 chapters of biochemistry and up to the present time the question 

 has not yet been settled whether or not the fat is hydrolysed 

 before it passes into the cells of the intestinal epithelium. There 

 is about no subject in which so many controversies exist or 

 have existed. 



It is beyond the scope of the present paper to discuss the 

 problems which have stirred the minds of the medical physio- 

 logists. But it may be justified to discuss briefly some of the 

 discrepancies and differences of opinion in invertebrate physiology. 



The comparatively simple problem whether or not Protozoa 

 digest fat, has been studied by many authors and almost every one 

 of them came to different conclusions. Ni^enstein 95) in his 

 paper on fat-digestion and -storing in infusoria, is ot opinion 

 that fat is digested easily and eagerly by these animals. In the 



