340 Hoyt: CULTURES OF SPIROGYRA 
days in 0.1 per cent Crone’s solution. The two samples contained 
approximately equal numbers of filaments. They were well rinsed 
in nontoxic water and then placed together in untreated tap water 
in a covered glass dish. Within a few hours the filaments from the 
stock jar showed decided injury, and, at the end of six days, 
when the experiment was discontinued, about one third of them 
were dead (II, 13). The filaments transferred from Crone’s solu- 
tion showed no signs of injury during the period (II, 14). This 
experiment emphasizes the facts, well recognized, but not always 
considered by workers with cultures, that the internal conditions 
of organisms are fully as important in determining their behavior 
as are the conditions of the surroundings, and that the past history 
of organisms (the sort of surroundings under which they have lived) 
greatly influence their internal nature. Comparable results cannot 
be expected, in such work as this, unless the living material used 
has been kept under uniform conditions for a considerable time 
previous to experimentation. 
Turning to the results obtained with ordinary distilled water 
(TABLE Itt), this was found to be extremely toxic, killing all the 
filaments of Spirogyra, except in a single instance,* in from one 
to nine days (III, 1). Redistilling this water in glass produced 
a decided improvement in some cases, but none in others (III, 2-6). 
Similarly, the samples of water obtained as above described, at the 
beginning, middle and end of the distillation run, varied greatly 
and inconsistently among themselves. The undistilled portion 
left in the boiler after redistillation had been stopped was always 
just as toxic as untreated water (III, 2a, 3c, 4e, 5e). Making from 
the distillate or from the undistilled residue (III, 4, 5) a 0.5 per 
cent concentration of Crone’s solution produced no improvement, 
so that this addition of nutrient salts failed to counteract the 
toxicity of these two waters. The addition of animal charcoal 
to the boiler during redistillation in glass usually produced no 
improvement over the water redistilled without the solid (III, 7, 8)- 
Furthermore, the undistilled residue from such redistillation (after — 
removal of the carbon) showed no marked improvement. Boiling 
with or without carbon (III, 2-10) is thus seen to have produced 
* In this case an unusually small amount of distilled water was used, in pro- 
portion to the number of filaments in the culture. 
