384 



BOTANICAL GAZETTE 



MAY 



curve would be practically the same whether we use as ordi- 

 nates PH values or cc. of CO2 produced. The curves are plotted 

 in such a manner that the abscissae represent time (in minutes) and 

 the ordinates represent the change in PH value corresponding to 

 either the relative amount of respiration, the relative rate of respira- 

 tion, or to both (as designated in the figures). The relative amount 

 of respiration is obtained by dividing the total change in PH during 

 exposure to the reagent by the total change in PH caused by the 



REL.RATEOFRESP 

 REL. AMT.OF RESP. 



2 



AB 



DD 



'^c 



OA 



a-e^-K--ar 



D' E' 



A' C 



60 



MINUTfeS 



Fig. I a. — Points showing relative rate and relative amount (identical in this case) 

 of respiration of Laminar ia produced by sea water containing A, 0.1 per cent chloral 

 hydrate; B, 0.1 per cent novocain; C, i per cent ether; D, o.i per cent cafifeine; 

 E, ethyl-bromide; controls in sea water (broken lines); see tables I A to E; each con- 

 trol bears the same letter (with a prime) as the experimental curve. 



same material under normal conditions during the same length of 

 time. The relative rate is obtained by dividing the change in PH 

 during one period by the change produced during a similar period 

 by the same material under normal conditions. The broken lines 

 in each case represent controls in sea water. The curve of each 

 control bears the same symbol and letter as the experimental 

 curve for sea water plus anesthetic, except that in the control the 

 letters are primed. 



Inspection of the results for o . i per cent chloral hydrate (fig. 

 la [A]; table I A), o.i per cent novocain (fig. la [B]; table I Bj, 



