315 



merous in one region of the cell (fig. 3), or they may be scattered 

 uniformly throughout the cytoplasm (figs. 2, 4, 5). 



The granules are seen best in dry smears treated with Wright's 

 blood stain, but they can also be demonstrated with the Giemsa 

 mixture after previous fixation in the fumes of osmic acid. However, 

 the preparations must not be exposed to the fumes longer than 25 

 to 30 seconds, as the granules are not seen after the longer exposures. 

 This is probably because the osmic fumes intensify the action of the 

 basophilic blue component of the staining mixture. 



The fact that the granules are always present in the so-called 

 'large mononuclear' cells and in the polymorphonuclears shows that 

 the}^ approach a true granulation in so far as they are always to be 

 found in cells of a certain type. Their tendency towards a radial 

 grouping about the centrosphere is also a character common to the 

 'special' granules in the leukocytes of mammals during their period 

 of differentiation. On the other hand, their variations in size, number 

 and distribution, and their affinity for the azure of Eomanowsky 

 mixtures places them nearer the ' azurophil ' granules as we know them 

 in the lymphoid cells of mammals. 



The granules in question must be classified as ' azurophil' granules, 

 but the facts enumerated above seem to indicate that they are some- 

 thing more than the ordinary azurophil granules of the mammalian 

 lymphoid cell. In Amblystoma the granules are variable in size, number 

 and distribution, but they are always present in cells of a certain type 

 which have reached a sufficient degree of differentiation, while in the 

 smaller lymphoid cells they may or may not be present, i. e., the time 

 at which they begin to differentiate is variable. The azurophil granules 

 are not of constant occurrence in any of the mammalian lymphoid 

 cells, and in this respect they resemble the azurophil granules of the 

 smaller and medium-sized lymphocytes of Amblystoma, but on the 

 other hand, no type of lymphoid cell in mammals contains such a 

 constant and permanent azurophil granulation as is found in the large 

 mononuclear leukocytes and polymorphonuclears of Amblystoma. 



These facts show that the azurophil granules of Amblystoma are 

 intermediate between the ordinary azurophil granules of mammahan 

 lymphoid ceUs and the true granules of 'special' cells. Functionally, 

 the amphibian polymorphonuclears correspond to the granular special 

 cells of the higher animals, as has been shown by Klemensiewicz, 

 Maximo w, Frbidsohn and many others. However, they never 



