Some toxic and antitoxic effects in cultures of Spirogyra * 
W. D. Hoyt 
In view of difficulties commonly experienced in maintaining 
algal cultures in the laboratory, it seemed desirable to make an 
experimental study of some of these difficulties, as was suggested 
to the writer by Professor Georg Klebs, and the present publication 
deals with a portion of such a study. The experimentation was 
carried out in the Botanisches Institut at Heidelberg in 1909 and 
1910, the facilities of these laboratories being made available 
through the kindness of Professor Klebs. The experiments to be 
considered below bear upon the preparation of a nutrient solution 
suitable for algal growth under laboratory conditions, and under- 
take a partial analysis of the relations of the aqueous aaa eas to 
the success or failure of algal cultures in glass. 
The alga used for this study was Spirogyra longata (Vauch.) 
Kg.,f brought from Algiers in the spring of 1906 and kept since 
then (until the winter of t909-10) in a north window of the 
Botanisches Institut at Heidelberg, with only small additions of 
tap water from time to time. At the time of beginning these 
studies the culture was healthy and showed vigorous growth, and 
the material seemed excellently suited for experimentation of the 
sort in hand; all the filaments had developed under closely similar 
conditions and were obviously adjusted to the conditions existing 
in the laboratory. In the experimentation it was thus possible 
to alter the culture medium without greatly changing the other 
environmental factors—e. g., light, temperature—under which the 
plants had developed. The last consideration is an important 
* Botanical Contribution from The Johns Hopkins pas No. 29. 
t Determined from Einfachste Lebensformen des Tier- und Pflanzenreiches, 
Eyferth, B., 3 Aufl. 1900. 
333 
