808 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
is often advisable to fix witli absolute alcohol for 24 hours, and stain with 
picro-carmine or aqueous heematoxylin. For spores or cells, the walls 
of which are not penetrated by these reagents, Tschirch’s borated 
carmine may be used. When coloured to the right extent, the prepara- 
tions should be studied in glycerin, Canada balsam, or essence of clove, 
after dehydrating by alcohol of about 80 per cent. 
Preparing Sections with Elder-pith.* * * § — Herr J. W. C. Goethart 
recommends the following method, where very thin sections are not 
required. A vertical slit is made in a cylindrical piece of pith, the pith 
being left much longer on one side of the slit than on the other, and 
the longer side is thoroughly soaked with alcohol. The object of which 
sections are to be made is then placed in the slit, and a thin platinum 
wire firmly bound round the whole. The whole is now moistened with 
alcohol, and placed in the microtome. The sections are then placed 
and examined in glycerin. 
Mounting Algae and Fungi, j — From practical experience, Mr. J. E. 
Humphrey strongly recommends, in the preparation of slides of 
Algae and Fungi, the discarding of all fluids and cements, and the use 
of glycerin-jelly as recommended by Dr. L. Klein, J which he finds 
applicable to all classes of Thallophytes, after hardening with osmic 
acid. Even the colour of the pigments is, in most cases, perfectly 
preserved by this process. 
The Preparation of Vegetable Tissues for Sectioning on the 
Microtome.§ — Mr. A. J. M‘Clatchie says, “ Vegetable tissues vary so 
much as to the amount of protoplasm, cellulose, and other substances 
contained, that the methods used for obtaining good sections from them 
must vary greatly. I have prepared and sectioned fungi, lichens, the 
cotyledons, plumules, hypocotyledonary stems, roots, root-tips of the 
cucumber, young pine-cones, young wheat-blades, lilac-buds, and bean- 
stems, with varying degrees of success. 
Lichens and the young firm cotyledons of the cucumber could be 
dehydrated, and permeated with paraffin much more rapidly than young 
meristemic tissue, or tissue composed largely of cellulose and water. 
The former may be placed in 50 per cent., 75 per cent., 90 per cent., 
and 100 per cent, alcohol, chloroform, chloroform and paraffin, and 
finally in paraffin at a temperature of 55° C., remaining in each from 
two to twelve hours, and good results will be obtained. But the 
meristemic and the thin-walled watery tissue must be treated differently, 
or the tissue will come through very much shrunken and distorted, 
worthless biologically. 
I have had the most success following the method described by 
Dr. J. W. Moll, in the ‘ Botanical Gazette ’ for January 1888. I have 
obtained good sections from all the material that I have treated in this 
way. I used a 1 per cent, solution of chromic acid and 20 per cent., 
35 per cent., 50 per cent., 75 per cent., and 90 per cent, alcohols for 
* Bot. Ztg., xlviii. (1890) p. 354 (1 fig.). 
t Bot. Gazette (Crawfordsville), xv. (1890) pp. 168-71. 
X Cf. this Journal, 1889, p. 140. 
§ Amer. Mon. Micr. Journ., xi. (1890) pp. 190-1. From Amer. Naturalist, 
July 1890. 
