406 Notices of Boohs. !J u b T » 



superficial resemblances, and would be unable to appreciate the 

 purposes which the machines were intended to fulfil. In like 

 manner, anatomists, from observation of apparent resemblances 

 in the structure of organs, such as the brain (of the specific 

 action of whose parts little or nothing is known), have some- 

 times, rashly, inferred a greater degree of affinity between various 

 animals than there is any logical ground for admitting." (P. 423.) 



We are disposed to take exception to certain of the physiolo- 

 gical postulates expressed by the author. Speaking of the 

 transmission of centripetal and centrifugal impressions to and 

 from the encephalon, he says — " The time occupied by the sen- 

 sitive nerves in conveying the impression to the optic thalamus, 

 and by the motor nerve in re-conveying the order of the brain 

 from the corpus striatum, is different in different persons." This 

 implies the belief that the optic thalamus is the centre for sen- 

 sation, and the corpus striatum the centre for motion. In face 

 of the observations of Louget, Brown- Sequard, and especially 

 of Vulpian, we consider that this view cannot now be held. 

 Sensation is experienced by animals from whom not only the 

 optic thalami but the whole of the cerebral lobes have been 

 removed. Again, an animal whose corpora striata have been 

 taken away is able to execute movements when irritated — move- 

 ments which are not merely reflex. 



A few errors of typography and spelling may be corrected with 

 advantage in the next edition. A redundant letter frequently 

 forces itself into the word " development," and a sentence reads 

 that at night in London " the absence of thoroughfare in the 

 streets enables the cabmen to drive fats." 



The author says he brings his work to a close "with some 

 regret," as it has afforded him many pleasant hours of thought 

 and research. We hope that he has not brought his great and 

 valuable researches to an end in the present work, but will con- 

 tinue to prosecute the task which, although he confesses it to be 

 a pleasure to himself, is none the less a lasting boon to Science. 



Geometric Turning. By H. S. Savory. London: Longmans 



and Co. 1873. 

 Mr. Savory has here given to the turner, amateur or professional, 

 a full description of a new geometric chuck invented by Mr. 

 Plant. And it is interesting to learn what ma} 7 be done with the 

 instrument described in mechanical parlance as a " chuck." 

 Supposing the reader conversant with the beautiful curves pro- 

 duced in geometric turning (for their beauty, although relying 

 upon the greatest simplicity of order, is too complicate for 

 description), it maybe stated that if the chuck were arranged 

 for all its loops it would produce 93,312, and at 100 revolutions 

 a minute would take fifteen hours to complete the pattern. 



