DEGENERATIONS FKOM LESIONS OF TEMPORAL CORTEX. 149 



however, regarding the paths which the connecting fibres pursue 

 in one part of their course, when passing from the auditory 

 nuclei to the above-mentioned ganglia. 



Eesults also obtained by Zacher ^ 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 fourth of the iks 

 pcdunculi 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 nature, and accord- 

 ingly 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 Terrier'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 throughout avoided, so as to escape 

 possible injury to the occipital cortex. Fig. 1 and Plate XVIII. 



1 Zacher, " Beitr. z. Kenntn. d. Faserverlaufs in d. Pes Pedunc, sowie iiber 

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



