Chapter XVII 



— 197 — 



Golgi Apparatus 



from the tip, they become transformed into a vacuolar canal con- 

 taining numerous corpuscles which take up the silver (Fig, 132). 

 Silver methods gave us similar results in other fungi (Endo- 

 myces Magnusii, yeasts) whose vacuoles are not filamentous but 

 begin as small spherical elements filled with metachromatin. The 

 silver methods make these elements appear as small vacuoles, 

 each containing one silver-staining body, whereas in the larger 

 vacuoles, arising from the coalescence of the smaller elements, 

 these methods bring about the precipitation of numerous silver- 

 staining corpuscles which correspond to metachromatic corpuscles. 

 The images obtained are here again similar at all points to those 



Fig. 134. — Pea. Various cells from the same root. 

 Kolatchev's method. 1, central cylinder; blackened cytoplasm 

 appears reticulate. 2, cortical parenchyma; chondriosomes fairly 

 well preserved, heavily blackened by the osmium, a few are 

 vesiculate. 3, adjacent cells; at left, only the chondriosomes 

 and plastids are blackened and strongly vesiculated; at right, 

 only vacuolar precipitates are impregnated. 4, Differentiated 

 cells above the meristem; only vacuolar precipitates are 

 blackened. 



produced by neutral red. Silver impregnations also bring out the 

 metachromatic corpuscles of some algae (Tribonema) and bacteria. 

 Research carried out by means of silver methods, regularly 

 controlled by vital observation in cells very favorable for this, es- 

 tablish the fact, therefore, that the vacuoles, whatever their con- 

 tents, have the property of reducing silver nitrate and of bringing 

 about in their interior the production of particles of metallic silver, 

 giving images analogous to those produced by vital dyes. On the 

 other hand, silver methods, although bringing out the vacuoles 

 very clearly, are not specific for them and sometimes the chondri- 

 ome (chondriosomes and plastids) may be impregnated also and 

 even the chromosomes (giving in that case superb mitotic fig- 

 ures). There is no alteration of the chondriosomes and plastids, 

 however, so that it is not difficult to recognize them when they 

 are blackened by the silver. 



