380 BOTANICAL GAZETTE [may 



inhibited the production of CO2, while the absorption of oxygen 

 continued. Kosinski ■ (12) found that low concentrations of 

 ether increased the respiration of Aspergillus, while higher concen- 

 trations decreased it. Lauren (13) and also Irving (ii) have 

 noted that respiration increases during anesthesia produced by 

 ether and chloroform. Tashiro (26) found that anesthetics 

 greatly reduce the output of CO2 by dry seeds. Bonnier and 

 Mangin (3), as the result of experimental work upon the influence 

 of measured quantities of ether upon flowering plants, concluded 

 that the respiratory activity is unaffected by anesthetics. It has 

 since been shown by Ewaet (6) that chloroform increases the respir- 

 atory activity in Elodea. 



The effect of anesthetics upon the respiration of marine plants 

 has received very httle attention. Harder (9) has made determi- 

 nations of the respiration of marine algae, but in no case has he 

 studied the effect of anesthetics. Pantanelli (22) has observed 

 that sea water, when half saturated with chloroform, reduces the 

 excretion of- CO2 to about one-half of the normal. His experiments 

 were very few, and no duplicate or control experiments were made. 

 The methods employed by Pantanelli and Harder often required 

 that plants be shut up air-tight, in flasks completely filled with sea 

 water, and left in this condition for several hours, analyses being 

 made at the beginning and end of these long periods. 



In the experiments of the writer on the effect of anesthetics 

 upon the production of CO2, the marine alga Laminaria was found 

 to be well suited to the purpose. Fronds were cut up into pieces 

 about 2 inches long. Each piece was rolled up loosely and inserted 

 into a piece of Pyrex glass tubing. This was closed at one end, 

 while a piece of paraffined rubber tubing was attached to the open 

 end. Sea water, of approximately the same temperature as the 

 material, was then added to the tubes and the rubber tube closed 

 by a spring clamp. The tubes were then brought very gradually 

 to the temperature (16° C.) of the constant temperature bath. 

 The tubes were kept dark by inserting each tube in a black- 

 enameled, collapsible tin tube submerged in the bath. Several 

 tubes were used as controls in each experiment. These contained 

 material in sea water without aoiy addition. The reagents were 



