No. 387.]. PLANT MORPHOLOGY AND PHYSIOLOGY. 209 
per cent solution, z¢., 42.5. In changing from 20 per cent to o, solu- 
tion growth ceased, to be renewed again in 30 to 45 minutes. On 
this renewal of growth the turgor force was found to be normal for 
the o solution, z¢., 7.5. Corresponding results were obtained with 
the weaker solutions. Thus, in changing from o to 4 per cent, re- 
covery was effected in about 1 hour, the turgor force being 12, że., 
normal for hyphe growing in such a solution. In changing from 4 
to o, growth was renewed after about 15 minutes. Botrytis gave 
practically the same results. Mucor was much more sensitive. It 
has a lower turgor force and would not stand a change higher than a 
4 per cent solution. In other respects it behaved like Penicillium and 
Botrytis. When nitrate of potash is used, turgor would seem to be 
a controlling force in growth. The checking of growth when the 
turgor is increased, as by change from a strong to a weak solution, 
corresponds to injury from cutting, że., is in the nature of a shock, 
the length of time growth is inhibited depending on its severity. 
Dr. W. F. Ganone: Some Appliances for the Elementary Study of 
Plant Physiology. — The author pointed out that investigation is in- 
directly aided by good elementary teaching, which diffuses its results 
and enlists sympathy and support, and as well attracts more and 
better students for the making of investigators. At the present time, 
too, there is a rapidly increasing tendency to introduce more physio- 
logical study into elementary courses in schools and colleges, which 
is producing a demand for simpler and less expensive physiological 
appliances. In elementary teaching it is qualitative results that are 
mainly sought, and hence much simpler and less exact appliances 
can be used than is possible in investigation where nothing less than 
the very best can profitably be employed. The author then exhibited 
and described some simple appliances developed in his physiological 
practicum in Smith College. These included a simple temperature 
stage, made of copper; an efficient clinostat ample for demonstrat- 
ing the principles of geotropism, heliotropism, etc., constructed from 
clockwork ; a simple and inexpensive self-recording Auxanometer ; 
an Osmometer made from burettes and Schleicher and Schuell’s dif- 
fusion shells ; a very simple apparatus for demonstrating the exchange 
of gases in respiration; a special germination box; an advantageous 
method of preparing a potted plant for the study of transpiration, 
and a simple method of graduating roots, etc., with insoluble India 
ink, which is applied on a stretched thread along which it runs by 
capillarity. 
