Ranson, F2bers 12 Lestons of the Brain. 187 
was unable to find any evidence of a regeneration of the spinal 
cord in these animals. 
Spinal Cord of Birds. 
Upon birds we have the observations of BROwWN-SEQUARD 
(4) (1851), who severed the spinal cord in pigeons and subse- 
quently found nerve cells and nerve fibers in the tissue joining 
the cut ends. Ina paper published in 1892 he reaffirms his 
conclusions without further experimentation (5). Scosso (29) 
(1891) also experimented with birds, but failed to secure any 
evidence of regeneration. The observations on reptiles and 
birds are so few in number and so contradictory in character 
that no definite statement can be made. A further study of 
these forms would be desirable. 
Brain of Frogs and Birds. 
Much less work has been done on the brains of amphibia, 
reptiles, and birds. Two researches have been recorded in this. 
field, each giving positive results, though neither has been con- 
firmed. DaNIELEWsky (9) (1891) completely removed the 
cerebral hemispheres of a frog; and after nine months found a 
new cerebral mass, a microscopic study of which revealed cells 
which were believed to be nerve cells. Von Voir (35) (1868) 
claims to have secured even more striking results on the 
pigeon. Five months after complete removal of the cerebral 
hemispheres in a young pigeon he found two new hemispherical 
masses, with a cavity in each. These masses, which were 
composed of nerve fibers and nerve cells, passed over into the 
crura cerebri. There has been no serious attempt to repeat 
these observations and they have neither been confirmed nor 
disproven. It would be profitable to apply to the study of the 
brains of the lower vertebrates the same methods that have 
been employed in the study of wounds in the brains of mam- 
mals, since there is nothing in this part of the literature to 
compare with the careful studies of CoEN, SANARELLI, TEDESCHI 
and TscHISTOWITSCH upon the mammalian brain. 
