ZOOLOaY AND BOTANY, MICROSCOPY, ETC. 297 



When insects require any preliminary treatment to make them 

 transparent, sncli as soda solution, the solution should be thoroughly 

 removed by washing with water, after which the specimens should be 

 taken out one by one, the superfluous water removed with blotting- 

 paper, and then thrown into the carbolic acid. 



The author has used carbolic acid instead of alcohol in mounting 

 stained sections of wood, with excellent results, and it is much cheaper 

 than alcohol. 



Injection Methods.* — Dr. H. Griesbach makes some observations 

 on this subject, with reference more particularly to his investigations j" 

 on the vascular system of the Acephalse. 



Whilst injection-masses which are fluid when cold are the simpler 

 and easier in use, those which are fluid only when warmed are indis- 

 pensable for the coarser vessels. 



For the observation of vessels with the naked eye or a lens, gly- 

 cerine simply may be used with the addition of a bright colouring 

 matter. 



Another mass, fluid when cold, can be made by heating equal 

 parts of white and yellow wax, and dissolving in oil of turpentine, 

 and, after cooling, the solution is mixed with olive or rapeseed oil in 

 which sulphate of lead has been ground up. The result is a whitish- 

 yellow syrupy fluid, very useful for many injections. Sulphate of 

 barium or iodide of lead may be substituted for the suljAate of lead. 

 By the addition of spermaceti to the solution in oil of turpentine the 

 mass can be made thinner. The sulphates and the iodide are not 

 dissolved, but are in a very finely divided condition. 



If an injected preparation has to be afterwards cut, it should be 

 injected with gelatine (fluid when cold), with or without glycerine. 

 The gelatine can be coloured with all kinds of colouring matters. 

 The canula cannot be too small. With this mass the author has ob- 

 tained beautiful dry preparations prepared as follows. The injected 

 foot of Anodonta or Unio, after being laid for a short time in alcohol, 

 was placed in oil of turpentine, and later in a mixture of the same 

 and paraffin and exposed to the air. It dries without any shrinking, 

 and sections can be made with chloroform. 



For gelatine masses fluid when warm, chloride of uranium can be 

 used, which dissolves in water, and by which the gelatine gets a 

 glistening yellow colour. The most effective masses are some of the 

 aniline colouring matters, especially the glistening ones, such as 

 Bieberich scarlet, crocein, tropseolin, &c. 



The author then discusses the relative advantages of injecting the 

 living or dead animal, and expresses a decided opinion in favour of 

 the former contrary to that of Sabatier. Whilst with the latter he 

 has obtained tolerable injections of the lacuna of the foot of Mytilus 

 edulis, it would be hopeless to attempt to fill the lacunae of the foot 

 of Anodonta or Unio after death. Further details are given as to the 

 injection of the lacunae in these subjects. 



* Arch. f. Mikr. Anat., xxi. (1882) pp. 821-7. 

 t See this Journal, ii. (1882) p. 605. 



