316 ' New Scientific Books 4 [Oct. 



but when she looked with her left eye only, the obscurity was 

 greater. When four fingers were held before her, she could see 

 two of them distinctly; the third she could distinguish, but 

 could not see plainly ; the fourth she could not see at all. 

 When she looked at three fingers, she could see two of them 

 pretty plainly ; the first, however, more than the second, and the 

 third sne could not distinguish at all. When she looked at two 

 £ngers, she could only see one distinctly. 



After she had recovered so as to be able to get out of bed, it 

 wfts discovered that, although she could only see one-half of an 

 object plainly, when held directly before her, yet, if it was moved 

 to her right hand, and she continued to look straight forward, 

 she could see the whole of it distinctly. On the contrary, if it 

 was moved to her left hand, keeping her eyes fixed as before, 

 ;she could not perceive any of the object at all. 



Dr. Wollaston does not notice this last circumstance in the 

 jTwtances he relates ; but it appears to me an additional confirm- 

 ation of his opinion. The defective vision was owing to the 

 insensibility of one-half of the retina of each eye ; and that was 

 occasioned in this instance, probably, by pressure on the right tha- 

 lamus nervi optici, where the nervous fibres thence proceeding (on 

 the supposition of this semi'deciissation with those from the left 

 thalamus), finally expand into the righthalf of the retina of each 

 ■eye. This part of the retina being insensible, the rays of light 

 which passed to it from objects on the left of the centre of vision, 

 produced no sensation. But when the eyes were kept fixed, and 

 the object to be looked at moved to the right of the centre of 

 vision, so that all the rays from it passed to the left and sound 

 jialf of the retina, then the whole of the object became visible. 



It should be remarked, that, although the sensation of only 

 the teft side of the body was impaired, yet it was the right half of 

 each retina which was insensible. — (London Med. and Phys. 

 Jouni.) 



JVimeiiestar, Tfov, 5, 1824. 



Article VIII. 

 NEW SCIENTIFIC BOOKS. 



PREPARING FOR POBLICATIOX, 



Mr. W. Phillips will shortly publish a new and improved Edition of 

 Ills Outlines of Mineralogy and Geology, for the use of young persons. 



The Fluxional Calculus ; an Elementary Treatise designed for 

 Students of the Universities, and for all those who desire to be acquainted 

 with the principles of analysis ; by T. Jephson, BD. 



Lectures on Astronomy, accompanied and illustrated by the 

 Astronomicon, or a Series of moveable Diagrams. By W. H. Prior. 



Travels of the Russian Mission through Mongolia to China. By 

 p« Timkowski} withno^es by ^. J. Klaproth. 2 vols. 8vo. 



