180 CYTOPLASMIC INCLUSIONS 



that the digestive granules and gastrioles of Protozoa, choanocytes, and 

 leucocytes are entirely comparable, and included all of these cells in his 

 vacuolar reaction. Faure-Fremiet (1909) and later Kedrowsky (1932, 

 1933) compared the segregation granules of Protozoa and vertebrate 

 tissues and found they were similar in appearance, staining reactions, and 

 function. Chatton, Parat, and Lwow (1927), on the basis of specific 

 microchemical reactions, compared the protein reserves in certain of 

 the Foettingeriidae with the vitellin of hen's eggs. Kedrowsky (1931) 

 and MacLennan (1936) have given figures of the formation of neutral 

 fat bodies in the Protozoa which are almost identical with the descrip- 

 tion and figures of Bowen (1929) in the relationship between Golgi 

 bodies and lipoid secretion in cells of the mouse. Examples could be 

 multiplied, but these are sufficient to emphasize the fact that there are 

 similarities as well as differences between protozoan and metazoan cells, 

 with respect to their cytoplasmic granules. 



The same difficulties with respect to the so-called specific staining 

 reactions arise in both Protozoa and Metazoa. In a study of echinoderm 

 eggs, Tennent, Gardiner, and Smith (1931) showed that not one ma- 

 terial, but many reduce osmium in the Golgi techniques. The presence 

 of more than one type of osmiophilic granules has been proved by 

 Mast and Doyle (1935) and MacLennan (1936) in Protozoa. Although 

 Kirkman and Severinghaus (1938) hold to the idea of a particular 

 Golgi substance, they bear witness to the occurrence of additional osmio- 

 philic materials: "One often finds small osmiophilic granules of uncer- 

 tain significance in Kolatchev sections, but they are present in addition 

 to the Golgi apparatus and appear to bear no relation to the latter struc- 

 ture." In neither group is there any evidence that there is a particular 

 Golgi substance, any more than a particular Golgi structure. 



There is also at times an embarrassing overlapping in the results ob- 

 tained from the use of Janus green and neutral red. These dyes were 

 found by Hopkins (1938) to stain the same vacuoles in the marine 

 amoeba, Flabelhda, and Uhlenhuth (1938) reports similar results in 

 the thyroid cells of amphibia. The mitochondria turn out to be not a 

 simple group but a complex group, as indicated by the distinction 

 between mitochondria and active mitochondria, or mitochondria proper, 

 by Parat (1927) and by Joyet-Lavergne (1926). 



Evidence is accumulating in both Protozoa and Metazoa that no type 

 of cytoplasmic granule (with the the exception of the centriole) can be 



