348 BOTANICAL GAZETTE [april 



Batelli and Stern (2) have found oxidation in finely ground 

 tissue and watery extracts. Their results have been criticized by 

 Warburg. 



Warburg (21) found that the finely ground red blood cor- 

 puscles of birds consumed less oxygen than intact cells. Unfer- 

 tihzed sea urchin eggs, cytolyzed in distilled water, consumed as 

 much oxygen as the intact eggs but produced no CO2. In fertilized 

 eggs cytolysis reduced the oxygen consumption by 90 per cent or 

 more. A fuller account of the literature seems unnecessary, as it 

 has been summarized by Warburg. 



It will be noticed that in the cases previously reported respira- 

 tion after death is greatly reduced or entirely lacking. The only 

 instance in which post mortem respiration is greater than in normal 

 tissue is that reported by Loeb and Wasteneys (ii), in which 

 unfertilized sea urchin eggs, cytolyzed by saponin, showed from 3 

 to 7 times the normal rate of respiration. It is of considerable 

 interest therefore to find that the respiration of Laminaria after 

 death may be much greater than when in its normal condition. 



The determination of the output of CO2 was made in the fol- 

 lowing manner. The increase in the hydrogen ion concentration 

 of sea water containing pieces of Laminaria (in the dark) served 

 as a measure of the respiration of the tissue. The decrease in 

 PH value was determined by the addition of a suitable indicator 

 (phenolsulphone phthalein) by comparing the colors with those of 

 a series of buffer mixtures containing an equal amount of the same 

 indicator. 



Each piece of Laminaria was kept for about half an hour in 

 sea water before beginning the experiment. This treatment 

 tended to obviate any effects of the shght wounding (19, 20). The 

 material was then rolled into a scroll and inserted into a Pyrex 

 glass tube (7) fused shut at one end and attached to a paraffined 

 rubber tube at the open end. Sea water, of the temperature of the 

 bath (16=1= i°C.), was placed in the tube and the latter inserted in 

 a black enameled collapsible tin tube in the bath. The sea water 

 surrounding the tissue (in the tube) was renewed several times 

 before beginning the experiment. A definite amount of sea water 



