524 GENCHO FUJIMURA 



and thoroughness. The following phrase is there employed by 

 him: ''Ein negatives Resultat beweist nichts gegen eine Reihe 

 positiver Resultat und man kann nur schliessen, dass Mislawsky 

 die Bilder nicht beobachtet hat, die seine Gegner unter Augen 

 hatten" (p. 785). This should incidentally prove to be a 

 pertinent comment on the theory of the excellent Italian 

 author, Levi. 



If we summarize the observations of the various authors 

 respecting the structures and functions of the glandular cells 

 described above, we may enumerate as constituents of the glanduar 

 cells, 1) plastosomes, 2) secretory granules, and, 3) secretions 

 (vacuoles), besides the protoplasmic stroma proper, and it would 

 be superfluous to state that of these constituents secretory granules 

 have a directly important relation to the glandular secreting 

 functions. The secretions are nothing else than a liquefication 

 or modified product of the latter and there is no alternative but 

 to assume that the secretory granules, once lost at secretion, 

 take their matrix mostly from the plastosomes, which latter, 

 being split up and separated in small pieces, gradually meet the 

 deficit so caused. Thus, the real state of glandular secreting 

 functions is already a thing which can be largely followed up 

 and made clear by means of minute histological investigations 

 to-day. 



Also the histological studies of the ductless glands — internally 

 secreting cells — have become very active of late years, and, 

 especially among those which have been carried on by the methods 

 of plastosomic study, we may enumerate the thyreoid and para- 

 thyreoid glands, suprarenal capsules (chiefly its cortex), Lang- 

 hans' islets of the pancreas, and the ovary. Of these organs, 

 the ovary has been used more often than the rest as the object 

 of study, and consequently, comparatively speaking, much is 

 known about it. I will therefore give a general summary of 

 the observations of the various investigators respecting this 

 organ, consider its structure and the relations of its internal 

 secretory functions, and then glance at the structures of the 

 other organs, thus contributing toward a histological account 

 of internal secretion in general. 



