182 
POPULAR SCIENCE REVIEW. 
form an interesting subject of study to our telescopists. At present Mars is 
tbe only planet well situated for observation ; he will continue to be a con- 
spicuous object in our evening skies throughout the quarter. Venus is 
throughout the quarter very unfavourably situated, passing her superior 
conjunction on May 8. 
BOTAXY. 
Difference between the Akazcja and Strychnia Plants. — The distinction be- 
tween these two is a matter of some importance to the physiological botanist, 
and it has been very clearly determined in a paper lately published by Dr. 
T. R. Fraser of Edinburgh, which he has been good enough to send us. In 
reference to the structure of the pith and wood-cells the differences are as 
follows : — In Akazga, the consists of complete parenchyma. Its cells 
have, in transverse section, a more or less regularly hexagonal form, and, in 
longitudinal section, they present the appearance of four-sided parallelo- 
grams. Their transverse diameter varies from to jg— of an inch, 
being usually, however, about ; while their longitudinal diameter is 
from — to — of an inch. The majority of the cells are indurated and 
marked by radiating canals. A few non-indurated cells occur irregularly 
throughout the pith, and these contain starch granules. I'he luood-cells have 
pretty constantly a diameter of g—g of an inch, and are greatly indurated, 
the cavity being so much reduced in size as to appear, in cross-section, like 
a point. Such a section also shows that the wood-cells are divided into 
regular four-sided groups ; by numerous medullary rays, which vary greatly 
in thickness— some consisting of only one layer of cells, and others of three 
or four. In Stnjchnos Nux-vomica, the pith is only slightly indurated ; and 
in the sections examined, its cells almost invariably contain starch granules j 
a very few nearly perfectly indurated cells are, however, present. These 
cells vary considerably in diameter, some being met with of of an 
inch, and others of The majority of the smaller cells occur at the 
circumference of the pith. The ivood-cells are of the same character as 
those of Akazga. The cylindrical tracts of delicate parenchyma are, how- 
ever, larger, and much more numerous than those in Akazga. 
Botanical Lectures at Cambridge. — The Botanical Professor will commence 
his course on Tuesday, April l‘i, in the south-western lecture-room of the 
mmseum, at 1 o’clock. They will be continued on Tuesdays, Thursdays, 
and Saturdays at the same hour. Gentlemen who wish to pass the special 
examination in botany for their degi'ee must obtain a card from the regis- 
try' ; by them no fee is paid to the professor. The fee required of other 
students is one guinea each for this course of lectures. 
The Priparation of Fungi. — At the meeting of the Botanical Society of 
Edinburgh on December 10, Mr. James English presented a paper on this 
subject. About three years ago he hit upon a method of preserving fungi, 
whic hhe then recorded. The process adopted is that of waxing the speci- 
mens, and thus preserving their natural pileus and stipe. Specimens pre- 
served in 1800 are now as fresh ns when first prepared. A series of fungi 
