Thompson — Degenerations from Lesions of Temporal Lobe. 183 



Results, also obtained by Zacber^ from an examination of four 

 brains with more or less extensive softening, contain the following 

 conclusions which bear upon this subject. First, that the corpus 

 geniculatum internum is directly connected with the two upper 

 convolutions of the temporal lobe, to which it stands in the same 

 relation that the external geniculate body bears to the occipital lobe. 

 Second, that fibres from the temporal lobe descend through the outer 

 f om'th of the pes peduneuU as far as the upper part of the pons. 



These results, though as we shall see in themselves perfectly 

 correct, did not, however, do away with the necessity for further 

 investigation, especially of an experimental natui'e, and accordingly 

 the following research was undertaken. 



Methods employed. 



Monkeys and marmosets were exclusively employed. Of the 

 former, macacus rhesus, macacus sinicus, and callithrix personata ; 

 of the latter, the common marmoset (hapale jacchus) were used. 



After being anaesthetised, the temporal lobe was exposed by 

 trephining, and a portion of the cortex removed down to the white 

 centre. This was effected by means of a small Volkmann's scoop after 

 the area had been circumscribed by a shallow incision. The whole 

 operation was performed aseptically ; after the cranial cavity had been 

 opened, however, no fluid was employed for contact with the brain 

 other than sterilised normal salt solution. The size and situation of 

 the removed areas varied. Some were confined to Ferrier's auditory 

 centre (apex of superior temporal convolution), but for the most part 

 they involved a considerably greater extent of cortex. The posterior 

 part of the temporal lobe was thi'oughout avoided, so as to escape 

 possible injury to the occipital cortex. Fig. 1 and Plate XIY., a. h. c. d. 

 represent the areas removed in certain of the experiments. 



In most of the experiments the motor area was not exposed, and 

 was never actually injured in any way. 



The wounds in every instance healed by first intention, and the 

 animals were allowed to live for periods varying from nine to twenty- 

 one days. They were then painlessly killed by an over-dose of 

 chloroform, and the brains and spinal cords hardened in Miiller's fluid. 

 Subsequently thin slices were stained in Marchi's solution, and cut in 

 celloidin. 



1 Zacher. '' Beitr. z. Kenntn. d. Faserveiiauf s in d. Pes Pedunc, sowie iiber 

 dieeort. Bezieh. d. Corp. Genie. Int." Arch. f. Psych, xxii. s. 654-698 (1891). 



2 



