1915] 



DAVIS ENZYME ACTION IN MARINE ALGAE 803 



action was observable, either by reduction of Fehling's or by 

 microscopical examination. 



In the experiments on the hydrolysis of various poly- and 

 disaccharides, checks were set up in which the usual amount 

 of " diffusion-extract ' ' was placed in distilled water. This 

 was to determine the reduction of copper, if any, due to the 

 "diffusion-extract" itself. In no case was there more than 

 a very slight trace that might have been due to other 

 causes than enzymic. However, it was thought that a 

 self-digestion series would more definitely determine whether 

 the hydrolysis of the carbohydrates of the slime could be 

 brought about by specific algal enzymes. With this in mind, 

 a series was arranged in which the flasks contained 50 cc. of 

 a water extract from each of the forms investigated. Checks 

 were set up in which the "diffusion-extract" was inactivated 

 in the autoclave. Toluene was used as an antiseptic and the 

 flasks maintained at a temperature of 22-23 °C. for two 

 months. Aliquot portions removed from time to time failed 

 to show the slightest trace of hydrolysis. 



It will be remembered that Tihomirov ('10) had found 

 osozone-forming sugars in the conceptacles of Ascophyllum 

 and Fucus that he thought might be dextrose and d-galactose, 

 possibly also fucose and arabinose. Thinking that these 

 might possibly have arisen from their corresponding an- 

 hydrides contained in the conceptacle slime, a self-digestion 

 series was set up with an extract from the abscised, crushed 

 conceptacles of those two forms. The Fucus was in a fruit- 

 ing state. The series were set up in duplicate, one kept at 

 room temperature and the other at 32-33 °C. Fehling's test 

 showed no hydrolysis after a month. 



Pentosans alone were then used as substrates. Two series 

 of flasks for each of the algae investigated were set up, each 

 containing a .5 per cent solution of gum arabic. 1 To one 

 series was added 10 cc, to the other 20 cc. of "diffusion- 

 extract," and the flasks placed at room temperature with 

 toluene as an antiseptic. No hydrolysis was apparent either 



1 The gum arabic was dissolved in water, then precipitated with several 

 volumes of 95 per cent alcohol to get rid of reducing sugars. 



