398 Chronicles of Science. [July, 
M. Alphonse De Candolle in his ‘“Géographie Botanique’—that species 
are of different antiquities, and to hope that as our knowledge of the 
floras of preceding geological epochs becomes more complete, it will 
by degrees make us better understand the present distribution of 
lants.” 
; It appears that M. Reveil, recently deceased, sent for com- 
petition to the French Academy an essay “On the Action of Poisons 
on Plants.” According to his observations, not only mineral but. 
organic acids, as citric and tartaric acids, in dilute solution, will 
cause the death of the plant which absorbs them. It is the same 
with several saline solutions and mixtures much diluted with alcohol 
and ether, which may be absorbed with impunity by animals. The 
committee to whom this paper was submitted, have marked their 
appreciation by the award of an honourable mention. 
Scortanp.— Vegetable Nosology.—This important but little 
understood part of Botany is attracting some attention. At the 
meeting of the Botanical Society of Edinburgh, Dr. Lauder Lindsay 
read a paper “On the Diseases of Plants in connection with 
Epidemics in Man and Animals.” The ‘ Lancet’ of the 14th of 
April also contains an abstract of Dr. Salisbury’s views and experi- 
ments on the Cryptogamic origin of disease. The fungoid origin 
of disease is no new opinion. Hight years ago, the late Dr. 
Mitchell, of Philadelphia, published a pamphlet on this subject, 
which was very favourably received. ‘The prevalence of certain 
diseases amongst plants, produced by microscopic fungi, and at the 
same time of certain infectious diseases amongst animals, was known 
even in the middle ages. The course which investigation has 
recently taken on this subject will doubtless lead to discoveries of 
great value. 
At the same meeting Dr. McNab contributed a paper “On the 
Development of Leaves.” He reduces them in all their varieties of 
form to seven types—1. Basifugal, or leaves with the leaflets 
developing first at the base; 2. Basipetal, the leaflets developing 
first at the apex; 3. The Cyclical type—leaflets developing. in a 
circle, ex. Lupinus; 4. The Divergent type—the central leaflets 
developing first, and those of the apex and base last; 5. The 
Simultaneous type—all the leaflets developmg together; 6. The 
Ternate type—ex. Thalictrum, Aquilegia, &c.; 7. The Parallel 
type. Dr. McNab thinks that both simple and compound leaves 
belong to these types, the difference bemg merely one of degree of 
development and not of type. 
We append to these views of Dr. McNab the following 
synoptical table of the types of nervation of leaves taken from the 
‘Physiotypia Plantarum Austriacanum’ of Professors Ettinghausen 
and Pokorny, a work recently published by the Austrian Govern- 
ment, as likely to prove interesting to English botanists. 
