432 THE CONTRACTILE VACUOLE 



of the structure. It has been observed that treatment of stained material 

 with turpentine or hydrogen peroxide results in the bleaching of most 

 structures other than the Golgi apparatus, which may have been black- 

 ened by the procedure; Golgi bodies resist even prolonged bleaching 

 effects of these agents. Structures which normally are blackened by the 

 Golgi technique, or any of its modifications, are not blackened if the 

 cell or tissue is first subjected to alcohol or dilute acetic acid. For these 

 reasons, and others which need not be mentioned here, the Golgi ap- 

 paratus is thought to be composed largely of lipoid substances. 



Together with the Golgi apparatus, mitochondria are generally con- 

 ceded to be invariably present in all cells. These structures, variously 

 called chondriome, chondriosomes, cytomicrosomes, and so forth, are 

 frequently present in the form of short rods or ovoid granules, although 

 the shape is not constant for different types of cells. Some authors main- 

 tain that besides the Golgi apparatus and mitochondria a third invariable 

 cytoplasmic constituent, the vacuome, is also present. Whether invari- 

 ably present or not, the vacuome is at least frequently found in cells. 

 The literature dealing with these structures is exceedingly confusing, 

 owing largely to the lack of a uniform nomenclature. Repeatedly several 

 authors have written of the same structure under different names, or 

 different structures under the same name. The lack of standard techniques 

 also contributes to the confusion. One of the most commonly used tech- 

 niques for differentiating between the Golgi apparatus and mitochondria 

 is staining of the tissue with a mixture of neutral red and Janus green; 

 mitochondria readily stain with the latter, and some authors maintain 

 that the Golgi apparatus is stainable with neutral red. The vacuome also 

 stains readily with neutral red, and on this basis it has been proposed 

 that the two structures, Golgi apparatus and vacuome, are identical. 

 Others have found within the same cell neutral-red stainable inclusions 

 which are not osmiophilic, and osmiophilic inclusions which are not 

 neutral-red stainable; so it appears that the two structures are not identi- 

 cal in all cells, but in some exist as separate entities. Furthermore, it is 

 sometimes claimed that osmiophilic bodies (the Golgi apparatus) are 

 derived from mitochondria (Janus-green stainable, but not osmiophilic). 

 If this latter is true, then one might expect to find in occasional cells 

 structures which are both osmiophilic and Janus-green stainable, although 

 such a situation has not come to the attention of the author. Unfortu- 



