196 



Other fresh-water forms such as Oscillaria, Chrococcus, Cosniarium, 

 Closterium, Desrnids and Diatoms were not killed in a solution of strych- 

 nine sulphate containing one gr. in 1,000,000 cc. of water. The movement 

 of the protoplasm even did not stop. I have not yet determined the exact 

 lethal concentration of strychnine sulphate for these forms. 



Marine forms of the Cyanophyceae (as Oscillaria and Rivularia); also 

 Diatomes; Chlorophyceae, as Cladophora and Enteromorpha; Brown Algae, 

 as Ectocarpus; and Red sea weeds, as Polysiphonia and others were not 

 killed in a solution of strychnine sulphate having one part in 100,000 of 

 water. Nor was the movement of the protoplasm stopped by this concen- 

 tration. A solution of the same having one part in 10,000 also had no 

 effect. 



A solution of the same having one part in 1,000 also had no effect. 

 A solution of the same having one part in 250 killed all the plants in 

 twenty-four hours, but the animals which happened to be present were 

 killed in seven hours. 



There are only a few animals that can bear transferring from salt to 

 fresh water and vice versa. One of these is the form Artemia salina, 

 which may bear such treatment, but in so doing it assumes a somewhat 

 different size and shape. As a rule animals that are transferred from salt 

 to fresh water or vice versa, show at first accelerated movements, but 

 these become rapidly slower and slower, death ensuing in most instances 

 in a few seconds. 



All the marine forms experimented with were killed in two hours by 

 a solution of strychnine sulphate containing .5 of a grain in 100 cc. of 

 water. 



The above mentioned marine forms were killed in a solution of co- 

 caine containing .5 of a gram in 25 cc. of water, in two and one-fourth 

 hours. 



