Chinese Journal of Physiology

30 W.C, MA, H. C. CHANG anp A. C, LIU OBSERVATION

The neutral red and Sudan III stained elements are located between the nucleus and the secretion granules. They consist of a number of droplets or rods with diameters larger than those of mitochondria and zymogen granules (figs. 33 and 34). The droplets are not uniform in size, the larger being situated below the secretion granules, while the small granules are usually found between the deeply placed zymogen granules. The droplets vary also in form. They may be somewhat elongated, rod-like, spherical or irregular.

It is probable that the red-stained droplets are able to coalesce, since a network is sometimes present. It may be mentioned that we have seen such a change to take place in the ciliated epithelium of the toad’s oesophagus during ciliary activity (28). The changes in the pancreas are apparently too slow to be followed in this manner. Professor Cowdry has succeeded, however, in observing the complete genesis of the Golgi apparatus from the neutral red stained granules in Plasmodium praecox (13). :

The droplets revealed by different neutral red methods, have been considered as vacuoles or granules within the Golgi area, but not as the Golgi elements themselves (3,34), The positive results of Ludford (22), Jasswoin (17), Zweibaum and Elkner (87), Chlopin (11), Arnold (2) etc., according to Bowen (9) “are all explicable on the basis of the known behaviour of this dye towards watery vacuoles”. Neutral red, however, is also soluble in lipoid. Furthermore, if oleic acid or lecithin is added to a watery solution of neutral red, the fat will remove the stain from the watery. solution—almost completely if the solution is dilute. In our judgment the neutral red-Sudan III droplets stained by our technique are at least as real as other cytoplasmic inclusions, for they can be extruded outside the cell body by the pressure of a heavy cover glass.

The droplets in the pancreatic cell as well as in the salivary glands change according to the functional state of the cell. In the loaded cell, they are very compact and chiefly located below the secretion granules, A few smaller red droplets may be scattered here and there throughout the zymogen granules (see figs. 17 and 33), When the secretion is being discharged, they become less compact and they are found more or Jess separate among the zymogen granules, their location being moved gradually toward the luminal end of the cell (figs. 5, 9, 13, 21, 25, 29, 84).