284 BOTANICAL GAZETTE [april 



open to some objections, which, however, may be more theoretical than practical. 

 From his obser\^ations on plants grown in the absence of certain salts, he draws 

 conclusions as to the role of a particular element — a time-honored but nevertheless 

 unsafe process. Some of these observations coincide with those of earlier observ- 

 ers, and others are to be added to the long list of specific effects previously recorded 

 after like experiments. We cannot enumerate the results in detail. Assuming 

 Reed's and all others as valid^ no one is yet in a position to interpret this im- 

 mense mass of data, many of them conflicting, and to frame any generalizations. 

 In his discussion Reed clearly recognizes that the elements may either enter 

 into the composition of some organ or substance in the cell, or without doing this 

 permanently may act as catalyse rs, or in some other way may condition certam 

 reactions. It is the varied possibilities within these categories that render useless 

 at present all conclusions regarding the role of an element. The causal nexus 

 is too intricate to be analyzed until far more knowledge of cell chemistry is avail- 

 able.— C. R. B. 



L 



Respiration and potassium cyanid.^Incited by the studies of animal physiolo- 

 gists on the effect of hydrocyanic acid and cyanids upon animal respiration, 

 ScHROEDER set out to determine the effect of potassium cyanid upon the respira- 

 tion of Aspergillus niger.^y Of course "respiration" here means the intake of 0, 

 and the output of CO^, processes which are quite independent of one another, 

 and Schroeder's results furnish further evidence, if any were needed, of this 

 independence. Such investigations can hardly yield, as the author hopes,^ satis- 

 factory "conclusions as to the chemism of vital functions," until it is possible to 

 make a much more exact analysis of the fixation of O^ and the evolution of COj 

 than is yet possible. Enough is known regarding the diverse sources of CO., 

 however, to minify the value of superficial researches upon such obscure phenom- 

 ena. The investigations themselves are extensive and thorough enough, but they 



necessarily deal with superficial phenomena. 



ScHROEDER finds both the fixation of O^ and the evolution of CO^ strikingly 

 reduced by potassium cyanid. The production of CO. is practically stopped, 

 but the consumption of oxj-gen is not. The author is uncertain "whether this 

 small intake of O, is to be considered as a vital process, or a purely chemical 

 phenomenon," a phrase which indicates an unfortunate state of mind regarding 

 "vital" processes. He does not think that the cessation of the evolution of CO2 

 is a valid mark of death. (Obviously not, since it is well known that neither its 

 evolution nor cessation has any definite relation to death.) The further distinc- 

 tions which he makes between the action of HCN on the respiratory process 

 •' as a primary- action .... and not as a phenomenon of death," seem quite 



Ignorance 



C. R. B. 



^' SCHROEDER, H., Uebcr den Einfluss des Cyankaliums auf die Atmung von 

 Aspergillus niger, nebst Bemerkungen iiber die Mechanik der Blausaure-Wirkung. 

 Jahrb. Wiss. Bot. 44:409-481. figs. 2. 1907. 



