Supplement to "'Nature," May 3, 1906 



apes showed that it did not respond to unipolar ex- 

 citation, and that partial ablation gave rise to no 

 interference with movement? Tlie author makes a 

 g:ood deal of the fact that he has examined three cases 

 of tabes dorsalis, and observed profound cortical alter- 

 ations concentrated in this area. He would argue, 

 therefore, that correlated systems of sensory neurons 

 were alone affected. Without denying the probability 

 of this fact, which has been put forward by previous 

 authorities, it may be doubted whether the evidence 

 is altogether satisfactory, for two of the cases were 

 admitted tabo-paralysis, and the other was not free 

 from suspicion. 



Chapter v. deals with the visual area. There are 

 two definite and distinct areas, named by Bolton visuo- 

 sensory and visuo-psychic. The distribution of the 

 first corresponds to the line of Gennari, and occupies 

 especially the region of the calcarine fissure; it is 

 therefore often spoken of as the calcarine, or more 

 properly the striate area. Campbell confirms Bolton's 

 work on the visuo-sensory area, and delimits the 

 second definable visuo-psychic area, which forms 

 a skirt to the first, and practically covers the re- 

 mainder of the occipital lobe. It is characterised 

 by a remarkable wealth of nerve fibres and curious 

 large pyramidal cells. In the chimpanzee and orang 

 analogous areas were demonstrated, but it was found 

 that they extended much more widely on the lateral 

 surface of the hemispheres. It is curious that Dr. 

 Campbell has not observed that in a very consider- 

 able percentage of lunatics' brains the visuo-sensory 

 (striate) area extends from lo mm. to 30 mm. 

 on to the external surface. Moreover, Eliot Smith 

 has shown that this condition exists in a very con- 

 siderable percentage of the brains of Egyptians. 



Connected within the sylvian fissure, and occupy- 

 mg the transverse temporal gyri, is a small but 

 important field characterised by coarse fibres and 

 large pyramidal cells. This the author calls audito- 

 sensory; the skirt of cortex circumjacent he terms 

 audito-psychic. These two areas correspond with the 

 prmiordial and intermediary myelogenic areas mapped 

 out by Flechsig. The author remarks that the re- 

 mainder of the temporal lobe is characterised by a 

 poverty in cells and fibres of large size. 



The angular gyrus is not endowed with any 

 specialised architecture, although clinico-anatomical 

 evidence shows that it has a special function connected 

 with word vision. Dr. Campbell does not even con- 

 sider the cortical localisation of impressions coming 

 from the semi-circular canals by the external auditory 

 nerves, although he describes cortical changes in a 

 case of deaf-mutism. 



The author admits that although histological re- 

 searches of previous observers leave hardly any- 

 thing further to be learnt concerning the morph- 

 oloev of the cell and fibre elements resident in the 

 cortex of the limbic lobe, " yet the exact cortical 

 localisation of the olfactory and gustatory centres is 

 sadly wanting." The lobus pyriformis is probably 

 the principal cortical centre, although not the sole 

 one, governing the olfactory sense. Its structure is 

 characterised by superficially placed clusters of stellate 

 No. 1905, VOL. 74] 



cells, and a tendency on the part of projection fibres 

 to reach the surface. 



The cell and fibre architecture of the hippocampal 

 area and cornu ammonis show characteristic features, 

 and yet the functions of these parts are obscure. 

 Neither do we know the function of the gyrus forni- 

 catus ; but the author decides against its being con- 

 cerned with common sensation by the fact that there 

 is a total absence of large fibres and large cells found 

 in other sensory regions. 



Histological observations show that the cortex of 

 the parietal lobe possesses all the cell laminae of, 

 and a similar arrangement of nerve fibres to, the 

 intermediate post-central area, but it differs in con- 

 taining a smaller number of special large pyramidal 

 cells and of large medullated fibres. The boundaries 

 of this region, however, are not very definite or its 

 characteristics very clear. Is it a fact that " a homo- 

 logous area can be traced phylogenetically throughout 

 the vertebrate series," or does the author really mean 

 mammals? 



The intermediate pre-central area is characterised 

 by a similarity of structure to the pre-central area 

 in the fact that there are large cells and coarse, 

 medullated fibres, but they are greatly reduced in 

 numbers. He also points out that the stellate cells 

 are much less abundant than behind the Rolandic 

 fissure. He regards this area as being a cortical 

 region presiding over complex later developed skilled 

 movements, which clinico-anatomical observations had 

 previously proved. Moreover, the area agrees closely 

 with the intermediate area of Flechsig mapped out by 

 developmental methods. He finds that the whole in- 

 ferior frontal convolution is similar in structure, and 

 he assumes, therefore, that it is similar in function, 

 and therefore governs the motor element in speech. 

 This argument is, however, not very convincing. 



Chapter x. deals with the remainder of the frontal 

 lobe, which he divides into frontal and pre-frontal. 

 The results of this chapter are disappointing, for it 

 might be expected that histological studies would have 

 thrown more light on the possible functions of this 

 lobe ; for the author states on p. 248 : — 



" Without adding materially to our knowledge of 

 the functions of the frontal lobes, histology throws 

 light on some of the observations of previous 

 observers." "No explanation can be given of the 

 truth that stimulation of the frontal lobe produces eye 

 movements." 



He rather exaggerates the poverty of fibres in this 

 region according to some authorities. 



Chapter xi. is concerned with the island of Riel, 

 which consists of two types of cortex, the anterior 

 similar to the lobus pvriformis, the posterior to the 

 adjacent first temporal convolution. The insula is 

 old, and it plays a more important part in primitive 

 mammals than in man. 



At the end of each chapter is a summary and an 

 index of references to the work of other observers on 

 the subject. Tlie book concludes with a valuable 

 addendum, part i. containing a comprehensive survey 

 of the cell and fibre architecture of the cortex of three 

 tvpes of mammals, the cat, dog, and pig. 



