l^u'f^Tjln'SS'fXt] NOTES AND MEMORANDA. . 65 
thinks it may be generally said that the carbonic acid is absorbed by 
the leaf and the mineral matter (in solution) by the roots. 
The Fossil Arctic Flora. — Under this head the same number of the 
*Annales' contains a review by the Count Gaston de Saporta of M. 
Oswald Heer's well-knov/n work ' Flora Fossilis Arctica.' 
The Formation of the S;pores in Mugeoiia genuflexa. — M. Eipart 
has published a good paper on the Formation of the Spores in this 
Alga, and has illustrated his views by a number of well-executed 
sketches. The author states that his latest observations perfectly 
confirm his earlier ones, and utterly go against the views pro- 
pounded in the third fasciculus of M. Rabenhorst's ' Flora Europcea 
Algarum aquas dulcis et submarinse.' His observations are of some 
importance, as many algelogists believe that the spores of all the 
genus are unknown. Dr. Eipart describes and figures them both in 
their earlier and more developed stages, and he has shown the fila- 
ment in copulation. — Annales des Sciences Botaniques, t. IX. 
NOTES AND MEMOKANDA. 
The Solution of Canada Balsam.— Mr. Jos. J. Forster, of New- 
castle-on-Tyne, sends us the following note : — Many people experience 
considerable trouble in getting balsam to harden on the slides they 
may have mounted. For some twelve months past I have avoided 
this difficulty by preparing it in the following way : — I got some 
very old balsam, and in a " cool oven " allowed it to thicken to a stiff 
paste, then mixed freely with benzole. The great advantage arises 
from the balsam setting as soon as the slide is cool, and in twenty- 
four hours being quite hard. 
Triple-bladed Section-Knife.— Dr. Maddox sends us the follow- 
ing : — In the early part of the present year, when making sections of 
various soft tissues, I felt the want of some method by which a double 
section might be cut so as to present, when removed, the opposite but 
contiguous surfaces of the part through which the section had passed, 
and which with the ordinary double-bladed knife is often quite 
impossible. This led me to forward drawings to Mr. Baker, instru- 
ment maker, of 244, High Holborn, for guidance, and to whose skill in 
carrying out my design I feel indebted. This section-knife now stands, 
I believe, as the first triple-section-knife offered to microscopists. Its 
construction will be easily understood from the figure. 
It consists of three separate solid blades (blade and handle in one 
piece), the middle one with nearly parallel surfaces, thinner than the 
