82 N. H. COWDRY. 



In my own material of the same species, I have been unable to 

 find the radiating lines and perhaps this may be due to the fixa- 

 tive which I have used, but I have observed the granules. The 

 granules in my preparations fixed in Regaud's fluid and stained 

 with iron hematoxylin are almost indistinguishable from the 

 mitochondria which I see in the surrounding plasmodium (Fig. 

 13). They are of the same shape except in some cases where they 

 are in very intimate contact with the vacuolar membrane and 

 flatten out upon it, which may be due to surface tension. It is 

 important to note that the mitochondria are not illustrated in 

 Harper and Dodge's figures which would lead one to suppose that 

 they have been destroyed by the fixative; so that our con- 

 clusion is warranted that the granules which surround the vacuole 

 and constitute the termini of the lines are more resistant than 

 the mitochondria to fixation. It is probable that the destruction 

 of the mitochondria may have been occasioned by the acetic 

 acid in the Flemming's fluid. We know that plasts generally are 

 more resistant to acetic acid than are true mitochondria, which 

 would lead us to suppose that the granules in question are plast- 

 like. This interpretation falls well in line with Harper and 

 Dodge's explanation of the significance of the radiating lines. 

 They regard them as "pathways by which materials are brought 

 in from the surrounding cytoplasm." I cannot agree with them, 

 however, in their interpretation of the significance of the nuclei 

 as morphogenic factors. I would be inclined, on the contrary, 

 to regard the granules as plast-like and perhaps truly formative, 

 as in the higher plants. 



Furthermore, Harper and Dodge ('14, p. 7) have described 

 certain interesting formations within the lumen of the capil- 

 litial tube. They say that: 



"The granular material in the interior of the capillitial thread 

 (Figs, i and 2) becomes less as the wall thickens and the spirals 

 appear, and as the thread matures it practically disappears 

 (Figs. 3 and 4). There is, of course, no evidence that granular 

 material as such passes from the interior of the thread into the 

 forming spirals. We are inclined to suspect that the stainable 

 granules in the interior of the thread are precipitation products 

 formed in fixation, and that in the living condition the capillitial 



