IN USE AT THE ROYAL BOTANIC GARDEN. 29% 
any way with resin, for I find that the resin is coagulated and 
that it forms in such cases a white or grey covering over the 
resinous parts, 
Method of Procedure in using Formalin. 
The density of the fluid makes it difficult to keep the specimen 
submerged, and methods such as were described for buoyant 
specimens in alcohol have usually to be resorted to. 
Specimens with waxy coatings are before preservation in 
formalin immersed for a minute or two in strong alcohol to wet 
the surface. The alcohol is not allowed to enter the specimen 
or to act upon it sufficiently to cause contraction of the object ; 
but if the surface be wetted in this way the specimen sinks more 
rapidly and the penetration of the formalin is facilitated. 
Formalin as a Preservative in Collecting. 
As a preserving medium for use on excursions and in collecting, 
the concentrated form in which it can be carried makes it con- 
venient,! this particularly so when collecting alge, where the 
concentrated formalin is added to the water—sea-water or fresh 
water according to the habitat of the alga—in the tubes in which 
the specimens are placed. At the same time, Penzig? points out 
that when collecting abroad it is not so good as alcohol, because 
with formalin the tin cases commonly employed in work of the 
kind cannot be used, but glass bottles, heavy and inconvenient 
in transport, have to be resorted to. 
6. Boric Acid. 
This is recommended by Chalon* as one of the best of a large 
number of fluids he has tried for preserving botanical specimens. 
The solution used was a saturated or 3 per cent. aqueous solu- 
tion, which was improved in some instances by adding 1 to 5 
per cent. sodium sulphate. 
I find the specimens, as with formalin, become flaccid, parti- 
cularly those of Class I. Colours remain for some time, but fade 
when the specimens are exposed to light. Penetration is not 
very rapid, and there is difficulty at first in getting the specimens 
1 Hornell, Laboratorium et Museum, 1900, pp. 85-89. 
* Laboratorium et Museum, 1901, p. 19. 
* Bull. Soc. Roy. Bot. de Belge, xxxvi., Part 2, p. 39. 
