Ii8 RESPIRATION 



remains at a level much higher than the output of carbon 

 dioxide. 



Similar observations have been made by others, thus 

 Thomas * found that wheat subjected to the action of ether 

 shows an increase of respiration followed by a decrease. 



Exposure to J-$ per cent, of ether is only stimulatory pro- 

 vided it be of short duration, an exposure of more than thirty 

 minutes resulting in death. Similarly the main observations 

 of Thomas have been corroborated and extended by Smith f 

 who used the hydrogen ion concentration method in finding 

 the rate of production of carbon dioxide in wheat seedlings. 

 It was found that the first effect of ether, used in concen- 

 trations of I per cent., 3-65 per cent, and 7-3 per cent., was 

 to depress the rate of respiration ; this was followed by a rapid 

 increase to above the normal rate, which was in turn followed 

 by a decline to much the same level in all concentrations of 

 anaesthetic, in times varying with the dose employed ; the 

 stronger the solution of ether used, the quicker the fall. 



Irwin, % using the corolla of Salvia, found that the effect 

 of a high concentration of ether is an increased intake of oxygen 

 and output of carbon dioxide, whilst at the same time the 

 acidity of the cell sap is reduced. The action of anaesthetics 

 on the lower plants results in reactions similar to those ex- 

 hibited by higher plants under like treatment. 



Gustafson § found that Aspergillus niger, subjected to the 

 action of ether, acetone, or formaldehyde, exhibits an increase 

 in its respiratory activity followed by a decrease. The use of 

 caffeine in saturated solution similarly brings about an increase 

 followed by a decrease, whilst a 0-5 per cent, solution results 

 in a decrease of respiration intensity. 



Similar results were obtained by Brooks || in his experiments 

 with Bacillus subtilis, for which plant ether is toxic in low, 

 0-037 t° I'l per cent., and in high, 3-65 to y-T, per cent., con- 

 centration. In strengths intermediate between these, the drug 

 acts as a stimulant to growth. Further, the action of ether 



* Thomas : " Journ. Gen. Physiol.," 1918, 1, 203. 



f Smith : id., 1921, 4, 157. J Irwin : id., 1919, I, 399. 



§ Gustafson : " Journ. Gen. Physiol.," 1919, I, 181. 



|| Brooks : id., 1919, 1, 193. 



