260 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi 



mica and glass by means of a transparent medium and 

 preserved in alcohol. The substance used was photoxylin, 

 obtained from Grlibler of Leipzig, from whom alone it can 

 be obtained. The advantage attaching to its use is twofold, 

 (1) rapidity of mounting, (2) transparency. Hitherto objects 

 mounted for the museum on mica or glass plates have been 

 either tied to the plate by thread or fixed to it by such a 

 medium as glue or this mixed with plaster of Paris, or similar 

 opaque substance. The objection to the tying process has 

 been that it takes a considerable time to prepare the object, 

 and that in handling delicate specimens hardened in alcohol 

 the thread often cuts through or breaks the specimen. On 

 the other hand, the opaque cements, whilst enabling the mount- 

 ing to be more rapidly accomplished, have the drawback Of 

 obscuring a portion of the object mounted. Dr Jost, Assistant 

 to the Professor of Botany in the University of Strassburg, has 

 recently discovered the value of the substance photoxylin — 

 a special preparation of Griibler's — and the process of mounting 

 with it was communicated to the exhibitor during a visit to 

 Strassburg in the autumn of last year. The procedure is as 

 follows : — The specimen to be mounted is taken from the 

 alcohol in which it has been hardened, and the surface 

 alcohol having been removed, it is placed on the plate of 

 mica or glass on which it is to be mounted. A few drops 

 of photoxylin are dropped on it at the points at which it is 

 to be fixed, and the mica or glass plate with the specimen is 

 then carefully laid in an open l)ath of 80 per cent, alcohol 

 and left there for about a minute. The photoxylin imme- 

 diately sets as a transparent jelly, and the specimen is thereby 

 fixed to the mica or glass plate, aiul may then be transferred 

 to the jar in which it is to be permanently kept, when the 

 oljject will be seen h(;ld in position upon tlie mica or glass 

 plate, but the medium by whicli it is so held is invisible. 

 Oi tlie diir;d)ility of tlie mount tlie exhibitor could not speak, 

 ])ut there are specimens so mounted in the Strassl)urg 

 P>otanical Museum of about a year old, and still in perfect 

 condition. Tho jtrocess is a most convenient one, easily 

 accomplished, and giving most admirable results, and should 

 be a great Ixjon to those who liave the care of museums in 

 wliich delicate objects are mounted and preserved in 

 alcohol. 



