766 THE CEREBRAL CORTEX. 



sensation, namely, a peculiar torsion of the lip and nostril on the same 

 side. Occasionally, however, the reaction is bilateral, and especially so 

 in the rabbit. The reaction is that actually induced in these animals 

 by the application of an irritant, such as a pungent odour, directly to 

 the nostril. . . . But while we can be more or less certain, from the 

 outward reactions, that subjective olfaction is aroused by stimulation, 

 it is an exceedingly difficult problem to determine whether smell is lost 

 by destruction of the same region." l In Terrier's earlier experiments 

 by this method, which were admittedly not very exact, he found, with 

 destruction of the lower temporal regions on both sides, indications of 

 impairment or abolition of the senses of smell and taste. In monkeys 

 operated upon by myself, in conjunction with Sanger Brown, 2 we were 

 unable to detect such impairment, even when the whole of both 

 temporal lobes was removed. We did not, it is true, remove the 

 hippocampus major as well, and in some animals small pieces of the 

 hippocampal convolution were left. Nevertheless, in spite of the very 

 extensive lesion in this region, the animals unquestionably gave very 

 distinct indications of still possessing both smell and taste. Terrier 

 has since repeated the operation upon another monkey, and obtained 

 evidence of the loss of both senses for a period of about two months, 

 after which time both senses appeared gradually to undergo recovery. 3 

 There is, therefore, not complete localisation of those senses to these 

 parts of the brain. Munk 4 has recorded the case of a dog, rendered 

 blind by destruction of the occipital cortex, which seemed also to have 

 lost the sense of smell, and in which it was found post-mortem that the 

 whole of the hippocampal gyrus upon each side w r as converted into a 

 thin-walled cyst. Luciani 5 got no evident deficiency of smell after 

 extirpation of the temporal lobe in dogs, but found olfactory disorders 

 to follow lesions of the gyrus hippocampi and of the hippocampus 

 major combined. 



A case of tumour in the right gyrus hippocampi has been recorded 

 by Hughlings Jackson and Beevor, in which the patient suffered from 

 subjective sensations of smell. 6 



It is probable, for various reasons, that the centre for the sense of 

 taste is anatomically in close association with the olfactory centre, but 

 neither experiments on animals nor clinico -pathological observations 

 in man have thrown much light upon its localisation. Terrier got 

 occasionally movements of the lips, tongue, and jaws in the monkey and 

 cat, on electrical excitation of the lower extremity of the temporal 

 region, 7 and interprets this as indicative of the calling up of subjective 

 sensations of taste. 



The localisation of tactile sensibility. Terrier was led by the 

 results of his experiments upon the hippocampal region of the hemi- 

 sphere, 8 to the conclusion that tactile sensibility is in every case 

 impaired or abolished, in proportion to the destruction of the hippo- 

 campal and inferior temporal region. It was, however, found by 



1 "Croonian Lectures," 1890, p. 119. 2 PUL Trans., London, 1888. 



3 "Croonian Lectures," 1894. 4 "Die Functionen der Grosshirnrinde," S. 130. 



5 Brain, London, 1885, vol. vii. p. 145. 



6 Ibid., 1889, vol. xii. p. 340. For other cases, see Ferrier, "Cerebral Localisation," 

 p. 126. 



7 Flechsig has supposed, but without presenting any convincing evidence, that the 

 sense of taste is connected with the anterior part of the gyrns fornicatus. 



8 Ferrier, Phil. Trans., London, 1875, pt. 2 ; Ferrier and Yeo, ibid., 1884, pt. 2. 



