566 SCIENCE PROGRESS 



cortex which formed the prelude to three years' further work at the Claybury 

 Laboratory upon "The Histological Basis of Amentia and Dementia," a valuable 

 monograph which appeared in vol. ii. of The Archives of Neurology. This 

 elaborate research, involving an enormous number of micrometric measurements 

 of the different layers of the cortex at different periods of life (viz. in fcetal life, in 

 early infancy, and in the adult both in health and disease, which Dr. Bolton has 

 since amplified and extended), formed the foundations of the premises upon which 

 he now supports his theories regarding the functions of the different cell laminae 

 of the cortex and the application of the same to the explanation of mental 

 disease. 



The author's researches certainly tend to prove that the outer or pyramidal 

 layer of cells "subserve the associative, psychic or educative functions in contra- 

 distinction to the organic or instinctive functions of the cerebrum which are 

 subserved by the inner polymorphic layer"; the middle or granule layer is, 

 according to the author, receptor in function. There is much to be said in 

 favour of this very important generalisation. Dr. Bolton's researches show that 

 it is the pyramidal layer which suffers most in dementia and there is a failure of 

 its development in amentia ; but it is doubtful whether the true insanities or dis- 

 orders of mind can be explained by histological changes in the cortex, so far as 

 these changes are recorded by the methods at present known. 



In the present work, a complete account of Dr. Bolton's researches will be 

 found, and this may be regarded as the most valuable part ; and if the author is 

 somewhat unmindful of the work of others and omits to mention important 

 investigations, being himself satisfied that he has solved all the difficult problems 

 of disorders and diseases of the mind by mechanistic explanations — at any rate it 

 cannot be said that he has not honestly laboured for twenty years at a most 

 difficult subject and produced a large amount of valuable work in support of his 

 views. 



It is a pity that Dr. Bolton has not given a bibliography, or even references, 

 to the authors he does quote ; such a misconception as occurs, for example, 

 on p. 67 might thus be avoided: "It has, however, been definitely stated by 

 Campbell in his recent monograph, which has attracted great attention, the 

 prefrontal region is of slight structural and functional significance." The Localisa- 

 tion of Cerebral Function is presumably the work referred to, which was published 

 in 1905, with the aid of a grant from the Royal Society ; and considering the 

 short period of time complete localisation by histological methods has been 

 attempted, and having regard to the fact that this work of Campbell was the 

 first of its kind published, it can hardly be spoken of as recetit. The author 

 gives two somewhat sketchy although not uninteresting chapters, one on 

 Language and Thought, the other on Feeling, Emotion, and Sentiment. But 

 justice can hardly be done to these important subjects in twenty pages, and 

 it would have been better if the author had omitted some of the chatty paragraphs 

 respecting " The mechanical employment of the language machine," and have 

 found space for mention of the Diaschisis theory of Monakow and a consideration 

 of Apraxia in connection with Aphasia. Again, to take an instance of many in 

 which the author is unconvincing in his arguments: on p. 415 he states "that 

 the living spirochete in the brain is a necessary accident to dementia paralytica, 

 owing to it being so difficult to get rid of it, rather than the cause of this particular 

 form of dementia paralytica." It is unnecessary to pursue the author further 

 in his questions throwing doubt upon the causal connection of the spirochetes 

 in the brain with the histological changes, since he stands at variance with the 



