478 DAVID H. DOLLEY 



the alteration in most pronounced degree and most frequently. 

 In the ether-morphine dog, there was a pecuUar phenomenon. 

 Only by prolonged overstaining could any chromatic substance 

 be demonstrated even in the nucleus. After several days these 

 diffuse blue nuclei were found changed to the typical brown of 

 the rabbit. 



The color at once suggests an associated pigmentary deposit. 

 Accordingly, a fine amorphous light brownish pigment was identi- 

 fied in many cells after all fixations in stained and unstained 

 sections in both cytoplasm and nucleus. However, the gross 

 amount of changed material is far from being entirely formed 

 pigment, and represents a transformation of the chromatic sub- 

 stance only demonstrable by staining. It is also to be noted 

 that pigment occurs in the cells of the granular layer and extra- 

 cellularly. 



The possibility of extraneous matter simulating the pigment, 

 which -is very troublesome where the pigment is scant and scat- 

 tered, was controlled as fully as was feasible. Unstained sections 

 were also mounted in xylol and in water, and the mercury material 

 subjected to a second prolonged iodin treatment in sections. 



There is no doubt that the pigment is derived from nuclear 

 substances. The observations above of the primary location 

 within the nucleus predicate that. On account of the uncer- 

 tainty which may still exist as to the nature of the so-called Nissl 

 substance, the genesis within the nucleus is fortunate with re- 

 spect to the genesis of the extranuclear deposit. For under the 

 conception of the extranuclear chromatic substance as chromidial 

 apparatus, extranuclear functioning nuclear material in the sense 

 of Goldschmidt ('04), which all the evidence obtained by me 

 corroborates for the nerve cell, one deals with a common origin 

 of pigment in both plasma and nucleus. The demonstration 

 may be made more conclusive by citing the evidence for the nerve 

 cell in terms of that from other sources. 



R. Hertwig ('04) described the transformation of chromidia 

 into pigment in Actinosphaerium eichhorni in the state of de- 

 pression. By the term chromidia, he designated excessive 

 chromatin which had been extruded from the nucleus to reduce 



