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Ganong Botanical Apparatus. 
GANONG BOTANICAL APPARATUS. 
A CATALOGUE of apparatus for use in plant physiology 
issued by the Bausch and Lornb Optical Co., and a first 
supplementary list are to hand. In them Prof. Ganong describes a 
number of pieces of apparatus devised by himself and made by 
Bausch and Lomb under his direction. They are intended 
primarily for demonstration and class purposes. Ganong has paid 
special attention to simplicity of construction and convenience of 
manipulation ; and in these respects he appears to have attained a 
considerable measure of success. The,apparatus is, on the whole, 
simple and ingenious, and would no doubt prove quick and easy to 
use. On the other hand the cost is, in some cases, prohibitive. 
Few laboratories could afford the luxury of the Autographic 
Transpirometer and Balance, costing in all about £40; and it may 
be doubted whether considerations of expense will allow of the 
ready adoption for class use of much of the other apparatus in 
place of rough and ready forms which can be made at small cost 
from materials available in a laboratory. For instance, when quite 
good starch photographs can be made and similar experiments 
performed with the aid of wire gauze and black cloth, with strips 
of sheet lead as clips, there is not likely to be much demand 
for a two guinea apparatus: the latter allows of more ready 
diffusion of C0 2 , but, as Ganong himself says, “ this is only a 
matter of degree.” 
The catalogue is nevertheless worth a careful perusal by all 
who are interested in the teaching of plant physiology. VVe may 
mention, especially, the potometer, a modification of the form with 
horizontal capillary, and the manometer, for root pressure experi¬ 
ments ; both reasonably cheap, and having distinct advantages. 
The wheel space-marker for marking off equal lengths along roots 
etc. in growth experiments is a decided improvement on the camel 
hair brush both in efficiency and economy of time. The leaf-area 
cutter for use in connexion with Sachs’ dry weight method is neat; 
but must be used with certain precautions to ensure trustworthy 
results (see Brown and Escombe, Roy. Soc. Proc., 1905, and 
Thoday, Roy. Soc. Proc., 1909, where a similar instrument is 
described). It would be an improvement if the leaf-discs received 
final drying in a tube which could be closed during weighing, as 
their leaf substance is frequently hygroscopic. The temperat u re 
stage has also much to recommend it, but it is difficult to see why 
it should not be quite as effective in a much cheaper form. 
D. T. 
R. Madley, Printer, 151, Whitfield Street, Fitzroy Square, W. 
