80 



INTRODUCTION TO CYTOLOGY 



plasm, and their blackened rim after osmic treatment strongly suggested 

 the discrete Golgi bodies of insect spermatocytes. Bowen concluded that 

 these elements, rather than the vacuoles, correspond to the Golgi material 

 of animals, an interpretation which he thought was supported by phe- 

 nomena in plant spermatids to be mentioned below. That the platelets 

 are not a special class of elements but chondriosomes or young plastids 

 showing a particular type of impregnation picture is claimed by several 

 observers.^* 



The third hypothesis, namely, that it is the plastid in plants which 

 most nearly corresponds to the Golgi material in animals, has been 

 advocated chiefly by Weier (1930a, 1931, 1932), although it had been 

 suggested by Bowen (1926c) only to be abandoned for the osmiophilic 





_ •♦« « • ■ / 



*^.% 





a b c d 



Fig. 42. — Comparison of Golgi zone and plastid. a, nerve cell of Bufo tadpole; silver 

 impregnation, b, spermatogenous cell of Polytrichum; osmic impregnation. Note 

 similarity of plastids in 6 and Golgi zone in a. c, Golgi bodies in spermatocyte of Helix; 

 osmic impregnation, d, plastid in sporogenous cell of Polytrichum; osmic fixation. (From 

 Weier, 1932; a and c after Parat.) 



platelet view. Weier has made a detailed comparison of the fixation 

 images of the Golgi region in animal cells as described by Parat and other 

 investigators with images obtained by similar methods (osmium and 

 silver impregnation) in moss cells. He finds a striking similarity in the 

 two series of cases. Before their characteristic activities begin, both 

 Golgi region and plastid may appear relatively homogeneous, but after 

 starch or the secretion product has accumulated each of them shows a 

 blackened constituent in the form of strands or plates running through 

 a mass of lighter substance or appears as a dense mass with one or more 

 "cavities" inside it (Fig. 42). Starch occurs in these regions in the plastid. 

 The dense substance and the cavities are compared respectively with 

 the modified cytoplasm and "secretory vacuoles" of Parat's Golgi zone; 

 the characteristic "network" or "platework" fixation image produced 

 in both cases is attributed to a general similarity in constitution. It 

 is concluded that the Golgi zone, like the plastid, should be considered 

 as primarily a specialized region of the cytoplasm having to do with the 



"Owens and Bensley (1929), Kiyohara (1930), Guilliermond (1928, 19296e). 

 Weier (1931) argues for their distinctness in mosses. 



