COMPARATIVE STUDIES ON RESPIRATION. 

 I. Introduction. 



By W. J. v. OSTERHOUT. 



{From the Laboratory of Plant Physiology, Harvard University, Cambridge.) 



(Received for publication September 6, 1918.) 



In the course of studies on antagonism the writer made experiments 

 on the action of antagonistic substances on respiration. As a re- 

 sult of his experiments he became dissatisfied with the existing means 

 of studying respiration in plants and undertook to devise more sat- 

 isfactory methods. At his suggestion Dr. Haas developed an indicator 

 method^ which proved to be very satisfactory for aquatic organisms. 

 However, it had serious limitations which were subsequently removed 

 by a method devised by the writer. The new method is accurate, 

 rapid, and convenient, and can be used for organisms of all kinds.^ 



A series of studies has been made in the writer's laboratory by the 

 use of these methods, the first of which are here brought together. 

 The work of Mr. Gustafson deals with higher fungi, that of Mrs. 

 Brooks with bacteria, that of Miss Thomas with flowering plants, and 

 that of Miss Irwin with a variety of animal material. The work of 

 Haas^ on the marine alga Laminaria was carried, out under the same 

 conditions, and may therefore be compared with the results described 

 in this series. 



In the first investigations the technique described by Haas^ was 

 employed in most cases. Phenolsulfonephthalein was added to the 

 liquid containing the organisms, and respiration was allowed to pro- 

 ceed until a definite change in acidity had occurred. Usually the 

 organism was then placfed in a fresh sample of the solution and the 

 process was repeated until the normal rate of respiration was ascer- 



^ Haas, A. R., Science, 1916, xliv, 105. 



2 Osterhout, W. J. V., /. Gen. Physiol, 1918, i, 17. 



3 Haas, Science, 1917, xlvi, 462; Proc. Nat. Acad. Sc, 1917, iii, 688. 



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