242 



Papers from the Department of Marine Biology. 



ACIDS AND ALKALIES. 



For ascertaining the effects of acids on the luminescence of Noctiluca, 

 hydrochloric (a lipoid insoluble) and benzoic (a lipoid soluble) acids 

 were used, the solutions being made up in a neutral artificial sea- water, 

 m/2(100 NaCl+2.2 KC1+2 CaCl 2 +10 MgCl 2 ), so as to avoid the 

 disturbing presence of the buffer phosphates and carbonates. 



Certain concentrations of these acids, n/2000 to n/4000 HC1 and 

 n/4000 CeHsCOOH, cause a bright continuous glow lasting from 20 to 

 60 minutes (table 4). The glow in these solutions becomes gradually 



TABLE 4. Effect of acids and alkalies. 



Solution in artificial sea-water. 



Luminous response. 



Color change 

 in neutral red. 



n/500 ton/1000 HC1. 

 n/2000 HC1 



n/4000 HC1. 

 n/8000HCl. 



n/16000HCl. 



n/500 to n/2000 benzoic . 

 n/4000 benzoic 



n/8000 benzoic. 



n/16000 benzoic 



n/125 NaOH (in Mg-free sea-water) 

 n/250 NaOH (in Mg-free sea-water) 

 n/500 NaOH 



n/1000 to n/2000 NaOH. 



n/250 NH 4 OH 



n/500 NH 4 OH 



n/1000 NH 4 OH 



n/2000 NH 4 OH 



n/4000 NH 4 OH . 

 n/8000 NH 4 OH . 



Momentary constant glow. 



Constant glow 30 min. (bright, be- 

 comes brighter, then fainter). 



Constant glow and normal response 1 hr. 



Normal 6 days (poor) ; momentary con- 

 stant glow at start. 1 



>6 days (exp. discontinued). 



Momentary constant glow. 



Constant glow 20 min. (becomes 



brighter, then fainter). 

 >6 days (poor) (exp. discontinued); 



momentary constant glow at start. 1 

 >6 days (poor); (exp. discontinued). 



Constant glow 2 min 



Constant glow 2 min 



Normal response 30 min., then constant 



glow 30 min.'' 

 Normal >7 days (exp. discontinued) . . . 



Constant glow 30 seconds 



Constant glow 75 seconds 



Constant glow 4 min. (faint) 



Normal 3 min., then constant glow 



6 min. 2 



Normal 5 days 



Normal >7 days (exp. discontinued).. . 



4 min. 

 10 min. 

 1 to U hr. 



None. 

 25 sec. 

 30 sec. 

 1 to 2 min. 

 None. 



None. 

 None. 



J The constant glow at the start is without doubt due to the dying condition of some of the 

 animals. 

 2 The normal response at the start is doubtless due to the delay in taking effect. 



brighter, stays at a maximum for some time, and then becomes gradu- 

 ally fainter. In n/4000 HC1 the animals also give a normal response 

 that is, they flash on stimulation while they are giving a steady glow. 

 Whether it is certain animals in the solution that give the one response 

 at the same tune that others are giving the other, or whether all of 

 the animals give both responses, it was not possible to determine. 

 Stronger concentrations of these acids kill the animals almost instantly, 

 while weaker concentrations have practically no effect. 



The alkalies NaOH (lipoid insoluble) and NH 4 OH (lipoid soluble) 

 have an effect upon luminescence similar to that of the acids, except 



