6 S. SAGUCHI 



there are present in the developing islet cells of the sheep embryo 

 minute safranophile granules. These have since been observed 

 by Laguesse ('95-96;' '01, '09-10) and by many other investi- 

 gators (Carlier, '96; Gianneh and Giacomini, '96; Diamare, '99; 

 Mankowski, '02; Ssobolew, '02; Pearce, '02-'03; Levi, '04; Mar- 

 chioni, '04; Tschassownikow, '06; Lane, '07-'08; Gelle, '11; Pi- 

 azza, '11; Bensley, '11-12, etc.). According to Laguesse, these 

 granules correspond in a general way to zymogen granules in 

 their behavior toward fixing and staining, differing from the 

 latter, however, in their smaller size and greater resistance to 

 acetic acid. Mankowski, Ssobolew, and Gelle call special atten- 

 tion to their affinity for safranin, while Carlier and Pearce desig- 

 nate them as eosinophile. Mankowski and Piazza have found 

 that the granules in question have the property of reducing sil- 

 ver nitrate, so that in silver preparations they take a brown or 

 black color. 



According to the above authors, the granules are not evenly 

 distributed throughout the islet cells, being abundant in some, 

 while other cells are almost devoid of them. On the contrary, 

 Lane and Bensley hold that there are two kinds of granules 

 which are present in different kinds of cells, both of which stain 

 with neutral gentian, although they differ from each other in 

 their behavior toward certain fixing reagents. 



That the protoplasm of islet cells assumes an alveolar appear- 

 ance in fixed preparations, caused by the presence of small vacu- 

 oles, has been shown by Laguesse ('9o-'96, '01, '09-'10), Diamare 

 ('99), Bensley ('11-' 12), Retterer and Lelievre ('13), and others. 

 Laguesse is of the opinion that these vacuoles are filled with clear 

 liquid which, when stained, presents under certain conditions a 

 gummy aspect. 



Fat droplets may also occur in islet cells. Dogiel ('93) no- 

 ticed certain corpuscles which stained black in osmic-acid solu- 

 tion; he claimed that they were fat globules produced in the pro- 

 toplasm in consequence of the regressive metamorphosis of the 

 cell. Laguesse ('09-'10), Stangl ('01), and Saleni ('05) have con- 

 firmed the presence of fat corpuscles in islet cells, without, how- 

 ever, attributing any special importance to it. 



