M8 The Philosoplvical Society of Glasgow. 



nor much beyond the laboratory. But they afford to practical men a 

 cheap and simple method of transferring works of art to glass, which 

 appears to me worthy of the consideration of those engaged in such 

 manufactures. When a picture is transferred to colourless glass the 

 figure is not seen by looking dii-ectly through it ; but as every line and 

 feature may be traced, it can easily be painted or coloured over, to bring 

 out all the beauty and art of the original, without further aid from an 

 artist. Tumblers and glasses, having a coloured band'^ut round them, 

 may have any suitable figure produced upon them, and at a cost little 

 more than the price of the printed paper. The only requirement on the 

 part of the operator is attention to the pasting of the picture on the 

 glass, and the time it is exposed to the acid. 



Professor Allek Thomson exhibited with microscopes a series of 

 preparations, illustrative of the minute structure of the spinal cord and 

 nerves, and gave a description of these preparations, together with 

 remarks upon the subject which they illustrated, from his own observa- 

 tions and from those of Dr. Thomas Reid, by whom a large series of 

 very beautiful microscopic preparations of the nerve-structures had 

 been made. 



The method followed in the construction of these preparations was 

 a modification of that recently employed by inquirers into this subject 

 viz., hardening fresh portions of the nervous texture by immersion for 

 some weeks in solutions of chromic acid, tinting them with a solution 

 of carmine, and, after various other subordinate processes of preparation, 

 mounting them in Canada balsam. 



Dr. Thomson pointed out the peculiar advantages of this process, 

 which have enabled microscopic inquirers in later times to investigate 

 with greatly increased success the more delicate textures of the nervous 

 system ; and, in proof of this, he contrasted the very exact knowledge 

 of these textures which is in the course of being obtained by anatomists 

 of the present day, with the results of the imperfect mode of dissection 

 which was followed previous to the introduction of the newer method. 

 In particular, he adverted to the great advantages obtained, in the first 

 place, by the use of chromic acid, in hardening the specimens so as to 

 admit of thin sections being made of them, while the minutest struc- 

 tural characteristics are preserved and increased ; and, in the next place, 

 by the process of tinting with carmine, which has the peculiar property 

 of colouring some parts of the nervous tissue more strongly than others, 

 and leaving some parts unaffected, so as to mark more clearly the dif- 

 ference between minute parts which could not otherwise be distin- 

 cruished. It is more especially the delicate central filament of the 



