695 
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
Plasma-cells are occasionally found in asthmatic sputum, and giant-oells 
in tubercular. 
By this method microbes of all sorts may bo demonstrated and 
enumerated. 
Negative Test for Blood-Spots.* — It is well known, says Herr F. 
Gantter, that it is not always possible to obtain lnemin crystals from 
old blood-spots on rusty iron. It is, however, possible to prove tho 
absence of blood. The action of peroxide of hydrogen on the merest 
traces of blood produces a scum of bubbles of oxygen. This reaction 
may be observed under the Microscope by placing on a slide a scraping 
of the suspected substance, and, after softening it by the application of 
weak alkaline water, adding some peroxide of hydrogen solution. If no 
gas-bubbles appear after the lapse of a short time, it is distinct evidence 
that there is no blood. The appearance of gas-bubbles, however, is not 
to be taken as a proof of the presence of blood, as other animal fluids, 
such as pus, give the same reaction. 
(3) Cutting*, including Imbedding and Microtomes. 
Handbook of Histology, f — Dr. W. S. Colman has issued a second 
edition of his work, which is intended as a practical introduction to 
histological methods for students and practitioners. This edition is 
enlarged, and has been in great part rewritten. The author says that 
he has selected for description those methods which have been found to 
work well in practice, and he has thought it better to describe a few in 
detail rather than give a short account of many similar methods. 
Those who have already found this book useful will no doubt bo 
glad to have this new edition of the author’s work. 
Microtome with new Device for f Raising and 3 Lowering! the 
Object.f — Dr. J. Nowak has sought to obviate the troublesome and 
* Zeitschr. f. analyt. Chemie, ii. (1895) p. 159. See Zeitechr. f.'ang. Mikr., ii. 
(1896) pp. 111-2. 
t ‘Section Cutting and Staining,’ 2nd edition, London, 1896, 8vo, viii. and 160 
pp. and 8 figs. X Zeitschr. f. wiss. Mikr., xiii. (1896) pp. 157-60. " 
3 B 2 
