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1904] . BRIEFER ARTICLES 393 
physiology is a movement to what may be called normal apparatus, 
viz., pieces manufactured especially for the particular purpose, yielding 
accurate quantitative results, capable of application to their work with 
convenience and economy of time, and purchasable from the stock of 
supply companies precisely as apparatus for physics and chemistry may 
be. With these ideas in mind I have been trying for some two years 
past to develop such pieces of normal apparatus for all of the principal © 
physiological processes, and some of the results are described below, 
while descriptions of others are to follow later. I have had in mind 
primarily their educational use, but they should also be available for 
investigation, especially the investigation of those physiological life- 
histories of plants which will form a leading feature of the ecology of 
the near future. In their construction, scientific efficiency (involving 
accurate mechanical workmanship), has been the first consideration, 
practical convenience and economy in manipulation the second, avail- 
ability for purchase by all who have the means and wish to buy them 
the third, while the matter of cost has come last. I have confidence 
that a people so devoted to efficiency, and so wealthy, as the Americans, 
will ultimately not begrudge the cost of really good educational appli- 
ances, though I expect that their introduction will be very slow. In 
order to make them generally available I have arranged for their manu- 
facture and sale by the Bausch & Lomb Optical Co., of Rochester, N. 
Y., who will presently be prepared to supply them along with other 
articles, chemicals, etc., needed for work in plant physiology. 
The reader interested in these matters will note that this is not the 
first attempt to provide such apparatus. Professor J. C. Arthur, of 
Purdue University, some years ago offered for sale several excellent 
pieces designed by himself, though apparently he has not continued 
their development. The field is open to all, and from the many pieces 
likely to be offered in the near future it is probable that the survival of 
the fittest will provide us with physiological apparatus of great exact- 
ness and convenience and of moderate cost. 
I. CLINOSTAT. 
tus in the laboratory of 
The most essential single piece of appara 
been invented, of 
plant physiology is a clinostat. Several forms have 
which the best known are the Pfeffer-Albrecht, the Wortmann, and the 
Hansen, all of German make and more or less costly and difficult to 
obtain, while several home-made forms have been described by Ameri- 
can botanists. 
