Vol. 4 No. I 



TORREYA 



January, 1904 

 PHYSIOLOGICAL APPLIANCES— I 



By George E. Stone 



Tlic appliances described in this series of notes have been im- 

 provised in the writer's laboratory during^ the past few years, 

 in connection with a physiological practicum, and while they 

 may not possess much value to the investigator, they have proved 

 useful in the students' hands. We realize that physiologists 

 have their own methods of demonstrating physiological phenom- 

 ena. Now and then, however, there appear in various journals 

 helpful sui^gestions in regard to demonstration methods which 

 the writer has found interesting and profitable, and it is hoped 

 those now to be offered may prove the same to others. 



Appliances for determining the Amount of Carbon 

 Dioxide taken up by Plants 



As a means of determining that plants take in carbon dioxide 

 under the influence of sunlight, the writer's students in physi- 

 ology have for some years made use of the following apparatus 

 with satisfactory results. 



Fig. I shows an appliance designed largely for experiments 

 with leaves. Briefly stated, it is a modification of the Winkler- 

 Hempel apparatus for gas analysis. The apparatus consists of a 

 bulb burette provided with a two-way stop-cock, and has an 

 aperture at the bottom, closed with a rubber stopper, for the in- 

 sertion of the specimens. The burette is graduated to -^^ c.c. 

 and has a capacity of 85 c.c. The method of using the apparatus 

 is quite similar to that of the Winkler-Hempel gas burette. The 



[Vol. 3, No. 12, of ToRREYA, comprising pages 177-201, was issued December 

 22, 1903.] 



