1^8 HODGE. [Vol. VII. 



acid crystals, particles of the above form were quite numerous, 

 but these also had no tendency to vanish. 



Grandis (i6) has obtained staining of intranuclear crystals 

 by long immersion in osmic acid. This was also tried, teasing 

 out the ganglion cells in osmic acid, but with uncertain or nega- 

 tive results. Miss Leonard (41, p. 39) also calls attention to 

 crystals or crystal-like bodies in the liver cells of frogs. 



Appearances of this form have a somewhat wide distribution 

 in avian tissues, so far as examined. I have found them in the 

 spinal and sympathetic ganglia of all birds studied, in the livers 

 of several, all which were examined for them, in the uropygial 

 gland of two (only ones examined), and in the secreting cells 

 of the oviducts of two fowls. They are most numerous in the 

 ganglion cells and oil gland, and occur somewhat sparsely in 

 the other locations. Absolute identity in these different cases 

 is, of course, not established, farther than such identity is indi- 

 cated by similarity between the forms observed. 



In general, as indicated in the figures (6 and 7, PI. VIII), 

 these figures are numerous in morning cells and fewer in those 

 of the evening, their place being represented by more or less 

 irregularly shaped vacuoles. It is as impossible to stain them 

 as it is to stain the vacuoles of the evening cells. In fact, as 

 they exist in the sections, I suppose they must be considered 

 vacuoles ; their uniform and definite shape, however, indicates 

 that they are produced by solution of some formed substance in 

 the cells. That they cannot be artifacts is proved by their form 

 and arrangement in the cells, by their difference in size in differ- 

 ent cells, by their greater numbers in morning material, and by 

 their entire absence from frog and mammalian tissues, treated 

 by the same methods. 



I will not attempt to describe these appearances more in detail 

 as to shape, size, and origin until further experiments are made. 



Conclusions. 



Metabolic changes in nerve cells are certainly as easy to 

 demonstrate, microscopically, as similar processes in gland cells. 

 They may be demonstrated equally well, and are the same in 

 character, either by artificial or natural methods. 



The principal changes thus far observed are : for spinal gan- 



