54 PLANT PHYSIOLOGY 



mostly of a precision character, are made by various scattered 

 individual "mechaniker," of whom the most important is Al- 

 brecht of Tubingen, who makes Pfeffer's best pieces. The 

 apparatus recommended by Detmer is all supplied by Desaga 

 of Heidelberg, and by Gallencamp & Co. of London, Eng- 

 land. Various pieces of normal and precision apparatus, largely 

 devised by Francis Darwin and his associates, are supplied 

 by the Cambridge Scientific Instrument Company of Cambridge, 

 England. In America there are four firms supplying instru- 

 ments of this character. The Cambridge Botanical Supply 

 Company of Cambridge, Mass., advertises many pieces which 

 are in part identical with, or else modified from, those de- 

 scribed in the first edition of this book, though made without 

 any co-operation of mine. A second is J. C. Arthur of Pur- 

 due University, Lafayette, Ind., who has devised several excel- 

 lent pieces (described mostly in the Botanical Gazette, 22, 1896, 

 463), and has had them made for sale by the University mechanic. 

 The third is the C. S. Stoelting Co. of Chicago, which offers 

 a few good pieces, without mention of the name of the inventor, 

 who is known, however, to be F. E. Clements. Finally there 

 is the Bausch and Lomb Optical Company of Rochester, N. Y., 

 which has undertaken the manufacture of such apparatus more 

 extensively and systematically than any other firm. They make 

 the various pieces of my own normal apparatus, and attempt 

 to supply all other materials and articles needed in Plant Physi- 

 ology, of which apparatus and supplies they issue a special 

 catalogue. 



