ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
711 
(6) Miscellaneous. 
Wethered’s Medical Microscopy.* — This little work, one of the 
numerous guides for the much-written-for medical student, is a good 
example of the compilations so frequently seen of late years. Its chief 
distinction is its title, which is inviting and alliterative. In the letter- 
press there is nothing particularly new except, perhaps, some spelling 
variations such as Schyzomycetes, Leucaemia, Jolgi ; but one original 
statement deserves a passing notice : the diameter of amyloid casts 
varies from almost one inch to not more than that of a red corpuscle. 
This is quite new. Casts of this larger size would not probably require 
the aid of a Microscope for their discovery, and might be fished up with 
a walking-stick. The work is apparently quite a compilation. 
Reactions of Callus and Paracallus.f — Mr. S. Le M. Moore gives 
the following microchemical reactions for true callus, and for the 
proteid substance which he distinguishes from it, under the name of 
paracallus. 
Callus rapidly dissolves on warming sections in Millon’s fluid, and 
displays no tendency to become red. It is soluble in boiling nitric 
acid ; hence the xanthoproteic test does not succeed. On running in 
caustic potash after sections have lain some time in copper sulphate, 
callus swells up, but does not turn blue or pink. After a good soaking 
in syrup, sulphuric acid swells callus so that it is almost invisible 
but it never assumes the slightest tint of pink. After many experi- 
ments with a peptic fluid, allowed to act as long as 86 hours, callus 
undergoes not the least change in form or general appearance ; and it 
now reacts quite normally with picric blue and corallin soda. The 
same result followed every attempt to dissolve callus in a pancreatic 
fluid (Fairchild’s pancreatic extract). 
Paracallus, on the other hand, stains yellow with picric blue ; takes 
a temporary pink with corallin soda ; does not swell up appreciably in 
sulphuric acid or caustic potash : is stained brown by iodide ; is not 
acted on by carmine ; and gives good proteid reactions. It frequently 
dissolves in a peptic as well as in a pancreatic fluid. 
* London, 1892, crown 8vo, 412 pp., with illustrations, 
f Journ. Linn. Soc. (Bot.), xxix. (1892) p. 232. Cf. supra, p. 630. 
