1915] 



DAVIS ENZYME ACTION IN MARINE ALGAE 805 



acid (sp. gr. 1.1). The flask was kept in the ice-box for two 

 weeks, when the oxidizing mixture was changed and the new 

 lot allowed to remain another fortnight. At the end of this 

 time a yellowish white tissue was obtained, representing fairly 



pure algal cellulose. This was filtered off, washed well with 

 distilled water, and dried in the oven at 75-80 °C. The final 

 product weighed 19.7 grams. 



This cellulose was used in a way similar to the filter paper 

 in the first series. One gram was placed in each flask and well 

 shaken up with 50 cc. of distilled water. A concentrated 

 " diffusion-extract' ' was prepared from Ascophyllum, Lamin- 

 aria, Ulva, and Chondrus, 10 cc. of which represented 5 grams 

 of the original dried tissue. This volume was added to the 

 flasks, and the series set away at 30° C. with toluene as an 

 antiseptic. At the end of two months no reduction of Fehl- 

 ing's was observable and under the microscope there seemed 

 to be no decomposition of the cellulose particles. 



Action on hemicelluloses. — Hemicellulose was used from 

 two sources — from date seeds, and from the seeds of the wild 

 persimmon, Diospyros virginiana. In both cases the experi- 

 ments were essentially the same. The horny coats were 

 broken and the embryos removed. Small pieces of the hemi- 

 cellulose were then taken, placed in a flask with water, and 

 heated in the autoclave at 15 pounds for 15 minutes to kill 

 the cytase present. Upon removal from the autoclave the 

 pieces were washed several times in distilled water, being left 

 in the last wash water for several days with toluene as an 

 antiseptic — this to get rid of any reducing sugars present. 

 Two of these washed pieces were placed in test-tubes with 

 10 cc. of the concentrated " diffusion-extract ' ' used in the ex- 

 periments with cellulose. Another lot was covered with 10 cc. 

 of distilled water and 2 grams of the dried algal powder 

 added. In a third series shavings of the hemicelluloses were 

 mounted in a Van Tieghem cell with a drop of enzyme solu- 

 tion. All the algae under investigation were tried out, but in 

 no case was there the slightest trace of decomposition, either 

 microscopically or by the reduction of copper. 



