THE EXTERNAL SECRETION OF THE PANCREAS AS A WHOLE 201 



granules were produced on the surface of the mitochondria. With the 

 advent of the electron microscope it was discovered that these granules 

 are not produced on the surface of the mitochondria but next to these 

 inside the endoplasmic canals. During the ist hour after pilocarpine 

 stimulation the number of these granules increases. When one cuts the 

 optical field down to a small part of the basal plasm, one sees that during 

 the first 3 hr. ~ lo to 40 granules appear in this field; then the number 

 decreases to almost zero, owing to the fact that the particles move away. 

 Thev show a population growth in the beginning of 100 to 150",, per 

 hour. 



Hirsch could show that there is a physiological connection between 

 these granules and the Golgi field. Figure 2 shows one of the many observa- 

 tions in which a single group of three granules was observed during 4 hr. 

 The "constellation" of these three granules "twinkled" for about an 

 hour moving irregularly to the Golgi-field where it disappeared by being 

 dissolved. The granules followed a zig-zag course, with a velocity of i /x 

 in 7 to 13 min. ; the smaller granules move faster than the larger ones. As 

 soon as a granule reaches the Golgi field it remains stationary and dis- 

 appears, i.e. it dissolves. The movement of the Hirsch granules from the 

 ergastoplasm to the cell apex was checked experimentally by three inde- 

 pendent investigators [39]. 



Are these granules of Hirsch identical with the intracisternal granules } 



Size: Hirsch's granules have in the light microscope a diameter of 

 03 to 0-4 /x. The intracisternal granules have a diameter of 0-2 to 0-3 /x 

 (Fig. 2). Both have the same size, both are visible in the light microscope. 



Chemical composition: Neither are lipoid drops, but contain mostly 

 protein, as was shown by Hirsch on his granules, and also by Siekevitz 

 and Palade for the intracisternal granules. Thus, I believe the two types 

 of granules are identical. 



What happens to these intracisternal granules after their movement 

 into the Golgi field .' There are some possibilities : either they develop 

 within the Golgi field through growth directlv into zymogen granules, or 

 they dissolve, and the dissolved parts are condensed in the Golgi field. In 

 case they are directly formed into zymogen granules then the process must 

 be visible in the light and electron microscope. Until now, however, all 

 investigations under physiological conditions have revealed that the 

 intracisternal granules disappeared in the Golgi field. Their "future" in 

 the Golgi field gave birth to several hypotheses, of which only one has 

 been upheld : the intracisternal granules dissolve, and their components, 

 which are more or less finished enzymes, are taken up by the Golgi bodies, 

 and in some way "packed" into the developing and enlarging zymogen 

 granules. This condensation of the parts of the intracisternal granules thus 

 becomes the major function of the Golgi field. 



