ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
363 
central body with iron-haematoxylin, any excess of the latter stain being 
removed by a decoloriser. Hence the term “ subtractive.” 
The author’s method has been chiefly applied to preparations from 
cutaneous eruptions. For obtaining a double stain the author satu- 
rates his material, say with orange or acid orcein, and then treats with 
inethylen-blue. 
(6) Miscellaneous. 
New Microcheniical Reaction of Chlorophyll.* — Dr. H. Molisch 
states that if tissues containing chlorophyll, which have not been 
moistened, are placed in a saturated aqueous potash-lye, the chlorophyll- 
grains almost immediately assume a yellow-brown colour, which again 
passes into green after about a quarter or half an hour. This reaction 
was observed in about 100 different plants, and even in material which 
had been kept a year in the herbarium. 
Use of the Quartz-Spectograph for Vegetable Pigments.f — Herr 
A. Tschirch describes the use of this instrument in observing the 
spectra of vegetable pigments; by its means the so-called terminal ab- 
sorption (of the violet and ultra-violet rays) can be resolved into bands 
Among the more important results which he has obtained are the 
following: — Xanthophyll is not an independent substance; he was able 
to crystallise from it a substance which he calls xantliocarotin , and which 
gives the so-called xanthophyll- bands in the absorption-spectrum of the 
extracts of leaves. Two distinct yellow substances are present in the 
yellow pigment of leaves, having entirely different spectroscopic pro- 
perties. There is a very close relationship between chlorophyll and 
haemoglobin ; the chlorophyll of leaves is a compound of phyllocyanic 
acid with some hitherto unknown substance. The close resemblance of 
the spectra of chlorophyll and of the blood is pointed out. By means 
of the quartz- spectograph the terminal absorption of the spectrum of 
chlorophyll was resolved into a broad absorption-band (VI.), which is 
much the most stable in position and intensity of all the bands, and is 
visible in the most dilute solutions. 
Demonstration and Crystallisation of Xanthophyll.J — Dr. H. 
Molisch has succeeded in separating the xanthophyll (carotin) within 
the leaf in the following manner. Small pieces of fresh leaves were 
placed in 40 per cent, (by volume) alcohol, in which 20 per cent, (by 
weight) of calcium hydrate was dissolved, and the solution left for 
several days in the dark until the whole of the chlorophyll had dis- 
appeared. If the calcium hydrate is now washed out, the xanthophyll 
can be crystallised out in the form of orange-yellow or orange-brown 
tabular or needle-like crystals, with a mother-of-pearl glance. They 
were obtained from about 100 different species, and vary greatly in form 
and arrangement, even in the same leaf. The author regards the xantho- 
phylls as forming a group of substances to which the general term 
carotin may be applied. The chemical reactions are distinct from those 
of cholesterin. 
* Ber. Deutsch. Bot. Gesell , xiv. (1896) pp. 16-8. 
t Tom. cit., pp. 76-94 (2 pis.). + Tom. cit., pp. 18-29 (1 pi.). 
