voi,.i.] Esterly— Poison Glands of Plethodon. 253 



The fibres in the perinuclear endings are of much the same 

 character as those of the muscles. Then' are many instances 

 which arc very clear of basket structure about the nuclei of the 

 Large glands (PL XXII, Figs. 21, 22. PI. XXIII, Pig. 30). 

 1 have in it In 'ci i able to discover connections bet ween the fibres and 

 the nuclei, though in at least one case (PL XXII, Figs. 23, 24) 

 the fibres end in knobs which lie directlj mi (he nucleus. The 

 latter seems usually to lie surrounded only by a basket of line 

 fibres. Bethe ('94) has described three sorts of endings on cells. 

 Of these he liuds that in the unicellular glands of the frog's 

 palate one frequently finds under the nucleus a small blue knob 

 which is connected with a fibre. The latter cannot, however, be 

 followed farther. 



In the case of the gland cells under consideration, there can 

 be no doubt that the nuclear basket is connected with nerve 

 fibres. That there should lie a nerve supply to the gland cells, 

 seems evident from the experiments of Drasch ('89), Eberth 

 ("49) and Loeb ('96) on Amphibian glands, and we have in 

 Plethodon histological evidence of such supply. The well- 

 known influence of the nervous system on the secretion of sweat, 

 for example, may be also mentioned in this connection. Herrick 

 and Coghill ('98, p. ."il) have suggested the possibility of a con- 

 nection between the nerves enveloping the glands, and the gland 

 cells, but were not able to demonstrate it. 



The objection may be raised that we are dealing here with 

 elastic instead of nerve fibres. This does not seem possible for 

 several reasons. The elastic fibres, as has been said, show very 

 little variation in size, and never, as shown by staining in orcein. 

 reach the excessive fineness of the nerve fibres. The branching 

 of the elastic fibres is much less frequent than that of the nerves, 

 and, in clearest distinction the former, as seen upon the glands. 

 take an almost uniform direction even in branching, straight 

 toward the epidermis, while the nerve fibres cross and recross and 

 branch in all directions, and the finest twigs show varicosities 

 which are never seen on the elastic fibres. The general effect of 

 the brown fibres in an orcein stain is entirely different from that 

 of the red ones in Mallory's stain, and leaves no doubt of the dis- 

 tinction here set forth between the elastic and nervous fibres. 



