186 ROBERT H. BOWEX. 



optical sections are always rings, while in case of the osmiophilic 

 platelets, the ring appearance holds from only one point of 

 view, the plates appearing as rods or ellipses when seen on edge 

 or obliquely. In the second place, in the hyacinth the plastidome, 

 pseudochondriome and osmiophilic platelets can all be demon- 

 strated in the same cell with osmic acid, and thus the distinction 

 between all three classes can be demonstrated (Fig. 3). Finally, 

 after blackening the osmiophilic platelets, it is sometimes possible 

 to counterstain with acid fuchsin, thus demonstrating the 

 platelets in black and the pseudochondriosomes in red in the 

 same cell. 



The Vacuome. In many kinds of cells I have found that 

 the vacuome can be impregnated with osmic acid, and thus 

 permanent preparations of great brilliance can be secured. Such 

 preparations have obvious advantages over the vital-staining 

 methods usually employed heretofore. Since the fact that 

 various methods designed for the demonstration of the animal 

 Golgi apparatus have been used with some success for demon- 

 strating the vacuome in plants, and since at some stages the 

 plant vacuome may assume net-like appearances, it has been 

 claimed by Gi.illiermond and others that the vacuome represents 

 the Golgi apparatus in animal cells. Quite apart from the 

 ultimate merits of such a claim, I wish to draw attention to 

 certain features presented by the vacuome after osmic treatment, 

 which at least suggest that the response of the vacuome to this 

 technical treatment may have little or nothing in common with 

 the blackening of true Golgi material. 



There is, in the first place, a distinct difference between the 

 action of the Weigl and of the Kolatchev methods. One may 

 work very much better than the other on a particular kind 

 of cell. Furthermore, the vacuome of some kinds of cells responds 

 regularly, of others irregularly, and of still others not at all, 

 to the same osmic treatment. In addition the type of response 

 differs. Sometimes the vacuoles as a whole (Figs. 5 and 7) 

 are intensely and evenly blackened; in other cases only more 

 or less well-marked traceries of black or gray mark the vacuoles 

 (Fig. 6), these traceries running perhaps through the substance 

 of the vacuole as well as over its surface. Thus the suspicion 



