THE CONTRACTILE VACUOLE 435 



not alter the possibility of such a functional relationship as he sug- 

 gested. 



Brown (1930) found that the Golgi apparatus of Amoeba proteus 

 is the characteristic protozoan type of globules and spherules, with 

 clear centers and dark rims. From a central focus these spherules appear 

 under the microscope to be crescent-shaped structures. He suggests that 

 the minute vacuoles which occur in the endoplasm of Amoeba are as- 

 sociated in some way with these crescent-shaped structures, and that 

 they unite to form the contractile vacuole. Brown further suggests this as 

 the reason that the vacuole in this form is not blackened by osmic acid, 

 as it is in Paramecium. 



Hall (1930a) found small globular inclusions in Trichamoeba which 

 are osmiophilic, and which resist bleaching by either hydrogen peroxide 

 or turpentine. These inclusions are similar in size and distribution to 

 those which are stained vitally by neutral red. In material impregnated 

 by the Kolatchev method, the contractile vacuoles are not blackened. In 

 material prepared according to the Mann-Kopsch method, small globules, 

 similar to those seen in the Kolatchev material, are blackened. These 

 globules likewise resist bleaching by turpentine and hydrogen peroxide. 

 In the Mann-Kopsch material, small vacuoles — two, three, or more in 

 number — are blackened in many amoebae. In a few instances a number 

 of blackened globules were seen adherent to the wall of the contractile 

 vacuole, which, on casual examination, gave the appearance of a vacuole 

 with blackened walls. Hall suggests that in material less effectively 

 bleached, such a condition might easily be mistaken for heavily impreg- 

 nated vacuoles. Nigrelli and Hall (1930) report the presence of small 

 osmiophilic and neutral-red stainable granules in Arcella vulgaris. 



Mast and Doyle (1935) apply the name "beta granules" to small 

 structures, usually spherical but sometimes ellipsoidal or rod-like in 

 shape, which have a diameter of about one micron. These granules are 

 distributed more or less uniformly throughout the cytoplasm, except at 

 the surface of the contractile vacuole, where they tend to become con- 

 centrated in a layer. Aggregation of granules on the surface was described 

 by Metcalf (1910), as previously mentioned. These granules, accord- 

 ing to Mast and Doyle, are stained vitally by Janus green, but only on 

 the surface, indicating that they have a differentiated surface layer similar 

 to that in mitochondria. In addition to beta granules, these authors in- 



