THE PRESERVATION OF CHLOROPHYCEAE 

 TABLE II— Continued 



225 



I'l.ASMOLYSIS 



2CLP 



3CLP 



8%. 

 10%. 

 12% 

 14%. 

 16%. 

 18%. 

 20%. 



2%. 



4%. 



6%. 



8%. 

 10%. 

 12%. 

 14%. 

 16%. 

 18%. 

 20%. 



green 

 green 

 green 

 green 

 green 

 green 

 green 



bright green 



green 



green 



green 



green 



green 



green 



green 



green 



green 



in the former and not in the latter. Again, in sodium chlorid, 

 Chaetophora is plasmolyzed in 2 to 3 % solutions and Spirogyra 

 in 1 to 2 % solutions, while in Amann's copper-lacto-phenol there 

 is plasmolysis in Chaetophora in a 12 % mixture but no plasmolj^- 

 sis of Spirogyra occurs in a 20 % mixture. Similar results were 

 obtained with Ripart and Petit's mixture. 



A good idea of the comparative results obtained with different 

 preserving mixtures of Vaucheria is given in table II. In experi- 

 menting with other algae different results were obtained so that 

 the general conclusion may be drawn that there is no one solu- 

 tion that will preserve all green algae equally well. The best 

 preservative for any alga and the concentration of the mixture 

 that will not cause plasmolysis must be determined by actual 

 experiment in each case. 



The mixtures containing chromic acid or mercuric chlorid proved 

 a failure in every instance. The chromic acid mixtures did not as 

 a rule cause plasmolysis, but there was no trace of the green 

 color left in the algae and the cytoplasm was usually colored brown 

 by the continued action of the acid. At first the mercuric chlorid 

 caused an olive coloration of the chromatophores and a blacken- 



