NERVUS TERMINALIS: MAMMALS 57 



Some attention was given to the arrangement of the chroma- 

 tophile granules in the cells. Carpenter and Conel ('14) have 

 pointed out the characteristic peripheral arrangement of this 

 substance in ganglion cells of the sympathetic system, and hold 

 this to be a distinguishing mark which differentiates them from 

 cells of the cerebrospinal system. The granules are said to be 

 scattered throughout the body of the perikaryon in gangUoD 

 cells of the central system. No very satisfactory- results were 

 obtained with the material available. Many of the cells (figs. 

 44 and 45) are seen to have a somewhat peripheral arrangement 

 of the granules, while the other cells figured do not give suffi- 

 cient indication of such distribution of granules to be noticeable. 

 It should be stated, however, that the sections stained with 

 thionin, which would affect the Nissl bodies, were too thick to 

 be favorable for such a study. 



An effort was made to demonstrate myeUnated fibers, if 

 present, and to learn, if possible in the large central roots of the 

 terminalis of the mule, the relative number of such fibers to the 

 number in the main peripheral trunk. The osmic acid, iron- 

 haematoxyUn, Weigert, and Stroebe methods were each tried, 

 with variations, a number of times. No success was had in 

 demonstrating myelin sheaths. In some of the preparations 

 dehcate fibers of smaU diameter were visible, but it was not 

 possible to trace them continuously through more than three or 

 four sections of a series. In the central roots from two to four 

 such sheath-like structures were present in some of the sections. 

 In others none could be seen. The peripheral bundle showed as 

 many as sixteen in certain sections. The results of this part of 

 the study were on the whole negative. Either the myehn 

 sheaths are not well developed in the nervus terminalis at this stage 

 of fetal life of the mule or the formahn preserved material did 

 not respond to the methods employed for their demonstration. 



The Horse. The nervus terminalis of the horse brain examined 

 (fig. 48) consists centrally of four principal strands which unite 

 near the base of the olfactory stalk to form a broad, flattened 

 nerve trunk. This trunk continues rostrally as a compact bundle 

 as far as the posterior part of the bulbus olfactorius, receiving 



