igig] HAAS— RESPIRATION 401 



the yellowish pigment comes out so rapidly as to interfere with the 

 indicator. As soon as the extraction of the pigment ceases (usually 

 ending during the first 2 periods), the color of the indicator is not 

 interfered with. When the concentrations of anesthetics are lower 

 than in those instances just mentioned, the pigment comes out (if 

 at all) so slowly as not to affect the indicator. This can be proven 

 by matching the solution obtained after any period (without the 

 addition of indicator) with the color of sea water (containing no 

 indicator) in a tube of equal diameter. In such cases no pigment 

 is detectable. 



Further evidence that it is CO2 that is being measured in the 

 experiments rather than other acids is the fact that by the use of the 

 gas chain it was found that Laminaria, after being 2 weeks in a 

 small quantity of unchanged sea water, had given off no acid other 

 than CO2. 



It might be supposed that the addition of so much alcohol as 

 24 . 2 per cent would dilute the buffer substances of the sea water so 

 that a given amount of CO2 added to the mixture would produce 

 more change in PH value than would be the case in sea water. This 

 was largely avoided by concentrating the sea water before adding 

 the alcohol, so that the amount of buffer substance remained the 

 same in the mixture as in the sea water alone. Tests made by 

 adding measured amounts of CO2 to sea water and to sea water plus 

 24 . 2 per cent alcohol (made up to the electrical conductivity of 

 sea water) showed that there was not sufficient difference in this 

 respect to be of importance in this investigation. 



Such experiments enable us to follow the respiration of the same 

 piece of tissue during shorter or longer periods of exposure to various 

 concentrations of anesthetics. They further show that in no 

 instance was there an initial decrease in the rate of respiration. 



It will be observed that when the concentration of anesthetic 

 is strong enough to produce any measurable result, the first effect 

 is an increase of respiration, which gradually declines and may 

 eventually fall below the normal. This decline is interpreted by 

 the writer as a toxic eft"ect. 



These results are not in accord with the statements of Tashiro 

 and Adams (27), according to whom anesthetics do not produce 



