ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
143 
Farrant’s medium : — Gum arabic, 1 ounce ; glycerin, 1 ounce ; 
water, 1 ounce ; arsenious oxide, 1J grains. Dissolve the oxide in water, 
then the gum, without heat ; when entirely dissolved add the glycerin, 
take care not to form bubbles; can be filtered through fine flannel. 
Specially recommended for delicate plant or animal tissues. 
Glycerin : — Concentrated or diluted with water, to which may be 
added a few drops of acetic or carbolic acid. For vegetable and animal 
preparations. 
Glycerin-jelly: — Glycerin, 120 grm. ; water, 60 grm. ; gelatin, 
30 grm. Dissolve the gelatin in warm water, add the glycerin, filter, 
if necessary, through flannel. All forms of glycerin-jelly must be used 
warm. For vegetable and animal tissues. 
Deane’s medium : — Similar to glycerin-jelly but with the addition 
of honey and a small quantity of alcohol. Used in place of glycerin-jelly. 
Glycerin-salicylic vinegar : — Glycerin, 1 vol. ; water, 4 vol ; salicylic 
vinegar, 0*1 vol. For Infusoria. 
Glycerin-salicylic vinegar for larvae, Hydra , Nematodes, &c. : — 
Glycerin, 1 vol.; water, 2 vol.; salicylic vinegar, 0*1 vol. Salicylic 
vinegar is made by dissolving 1 part salicylic acid in 100 parts pyro- 
ligneous acid, sp. gr. 1 * 04. 
Goadby’s medium : — Corrosive sublimate, 0*25 grm. ; alum, 60 grm. ; 
boiling water, 2300 grm. 
(3) Cutting-, including: Imbedding: and Microtomes. 
Imbedding Seeds by the Paraffin Method.* — Mr. W. W. Rowlee 
writes : — “ The modifications that may be made of the paraffin method 
of imbedding objects for sectioning are very many. There is always, 
however, some danger of shrinking delicate and very soft plant tissue. 
This is due to the use of heat in the process of infiltration ; and probably 
some of the non-heat-employing methods will be found preferable where 
such delicate tissue is to be imbedded. But for objects that will with- 
stand this process of infiltration, the paraffin method has many advan- 
tages over others. Imbedded in paraffin, objects are held firmly, and 
may be preserved as long as desired without further attention. 
For imbedding mature seeds I have found nothing equal to paraffin. 
The texture of the seed is often very dense, and offers much resist- 
ance to the knife. For this reason I found it better to use the harder 
grade of paraffin. A second serious difficulty that was met with in 
imbedding seeds was the fact that there was little, if any tissue con- 
necting the embryo j - with the seed-coats. Thus it would happen too 
often that just as the sections were being taken through the middle of 
the seed — and the most valuable ones are those near the centre — the 
embryo would leave the coats and the whole series would be spoiled. 
The inner surface of the inner coat in many seeds is highly polished, 
and as soon as there is nothing to retain the embryo but its adhesion to 
the coat, it will loosen. The paraffin does not hold the two together as 
would be expected. It was suggested that, in order to soften the tissue 
* Amer. Mon. Micr. Journ., xi. (1890) pp. 228-30. 
f The term “ embryo ” is used here where on some accounts it would be better to 
use the word “ nucleus.” The embryo is often but a very small part of the substance 
contained within the seed-coats. 
