COMPARATIVE STUDIES ON RESPIRATION. 

 XIX. A Preliminary Stage m the Progress of Ether Anesthesia. 



By EDITH PHILIP SMITH. 

 (Front the Laboratory of Plant Physiology, Harvard University, Cambridge.) 



(Received for publication, September 1, 1921.) 



One of the fundamental aspects of the action of the anesthetics is 

 their effect upon respiration. In order to study this under condi- 

 tions where the anesthetic is the only variable, it is desirable to em- 

 ploy plants, since experiments with animals are usually complicated 

 by muscular action and its influence on the rate of respiration. Under 

 suitable conditions the rate of respiration in plants remains remarkably 

 constant for periods of time considerably longer than the average 

 experiment, so that they offer good material for this type of work. 



The method employed in the writer's experiments was that de- 

 scribed by Osterhout.^ The material used was wheat, which was 

 chosen because it is easy to grow, and gives very constant results. 

 The wheat was a pure strain, supplied by the Minnesota Experimental 

 Station, and was particularly well suited to the purpose, being uni- 

 form in growth and showing a high viability. The seeds were germi- 

 nated with aseptic precautions, being grown in sterile paper cups 

 in a saturated atmosphere in the dark. The greatest care was neces- 

 sary to avoid contamination by molds, and the most effective 

 way of checking them was found to be that of soaking the dry seeds 

 for at least 10 minutes in full strength commercial hydrogen peroxide 

 before germinating. Cultures showing the slightest sign of molds 

 were rejected, as they gave aberrant results. It was found that by 

 allowing no liquid water in the cultures after the roots had begun to 

 emerge, but by keeping the atmosphere saturated (by means of a 

 bell jar inverted over the Petri dish full of water in which the paper 

 cups stood), the seeds produced ^an abundance of very well-developed 



» Osterhout, W. J. V., /. Gen. Physiol., 1918-19, i, 17. 



157 



