XXVi JouRNAL OF COMPARATIVE NEUROLOGY. 
The Dorval Spino-cerebellar Tract.' 
Sections of the sprmal cords of dogs at different thoracic and cervi- 
cal levels show that the longest fibers of the’ direct dorso-lateral cere- 
bellar tract, i. e., those arising in the lowest levels of the spinal cord, 
are most superficial in position and that the shorter fibers are added 
successively along the inner side of this zone. 
The authors verify previous findings of degeneration in the cells 
of CLARKE’s column below the lesion after section of the dorso-lateral 
cerebellar tract. In these cases the fibers of the tract between the de- 
generated cells and the lesion show no degeneration under the MARcul 
procedure, WEIGERT stain, anilin blue-black, picrocarmine, etc. To 
test the condition of these fibers further the authors made a right lat- 
eral transection of the Xth thoracic segment 260 days subsequent to a 
total transection at the IId thoracic level. The animal (dog) was sac- 
rificed 20 days after the establishment of the second lesion. The 
right cerebellar tract above the second lesion was found fully present- 
ing all the signs of WALLERIAN degeneration under the MARCHI re- 
action. The left cerebellar tract appeared normal and without any 
degeneration. ; 
‘It would seem therefore that atrophy, severe and long-lasting, 
probably permanent, of CLAaRKE’s cell-column induced by spinal tran- 
section in the the lower cervical or upper thoracic region, far from de- 
stroying the dorsal cerebellar tract, leads to no obvious or easily de- 
monstrable degeneration of at least the main body of the fibers of the 
tract. Further, after the severe atrophy of CLARKE’s column has set 
in and become established, transection of the tract in the very region 
of atrophy of the cell-column still causes full WALLERIAN degeneration 
of the fibers head-ward of the transection.” These results obviously 
have an important bearing on the theory of the physiology of the neu- 
rone and its biological interpretation. CC. 4 
The Optic Chiasma in Symmetrical and Asymmetrical Teleosts.* 
The author in continuing his observations on the optic chiasma of 
fishes develops several results which bear directly onthe morphology 
and phylogeny of the flat fishes. He has previously shown’ that in 
* SHERRINGTON, C. S.and LAstetr E. E. Remarks on the Dorsal Spino- 
cerebellar Tract. Journ. of Physiol., XXIX, 2, March, 1903. 
2 Parker, G. H. The Optic Chiasma in Teleosts and its Bearing on the 
Asymmetry of the Heterosomata. Aull. Mus.;Comp. Zool., XL, 5, 1903. 
’ The Crossing of the Optic Nerve in Teleosts. Biol. Bull., 11, 1901, pp. 
335-336. 
