[Vol. 2 



794 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



j 



In addition, at the end of a complete carbohydrate series there 

 were included for each alga the following checks : 



1. 50 cc. distilled water, 10 cc. enzyme diffusion. 



2. 50 cc. distilled water, 10 cc. enzyme diffusion. 



3. 50 cc. distilled water, 10 cc. boiled enzyme diffusion. 



4. 50 cc. distilled water, 10 cc. boiled enzyme diffusion. 



Where the enzyme diffusion referred to above actually con- 

 tained carbohydrases, it was extremely difficult to render them 

 inactive by heating — 10 minutes at the boiling point not being 

 sufficient in most cases to more than slow down the action. 

 This was probably due to the impurities contained, the rela- 

 tively large amounts of protein and slime present tending to 

 protect the enzymes. Those extracts relatively richer in such 

 constituents proved the more difficult to render inactive. The 

 expedient was finally adopted of placing the enzyme material 

 in the autoclave and bringing the pressure in the latter up to 

 15 pounds. This proved quite effective. 



THE CARBOHYDRASES OF ULVA LACTUCA 



The effect of an extract of Viva lactuca on different starches. 

 Since starches were to be used in many of the following 



TABLE II 



THE ACTION OF ULVA LACTUCA "DIFFUSION-EXTRACT"* UPON CERTAIN STARCHES 





15 days 



30 days 



Starch 



50 cc. 



1 per cent 



Sugar as 



glucose 



in 5 cc. f 

 mgms. 



Iodine test 



Sugar as 

 glucose 

 in 5 cc. 

 mgms. 



Iodine test 



Potato 



10.1 

 9.8 

 9.9 

 6.3 

 8.7 



Blue, trace red 

 Blue, trace red 

 Blue, trace red 

 Blue 

 Blue 



17.4 

 16.9 

 17.1 

 10.8 

 15.9 

 Trace % 



Complete hydrolysis 

 Complete hydrolysis 

 Complete hydrolysis 

 Reddish purple 

 Traces dextrin 



Arrowroot 



Wheat 



Corn 



Soluble 



Inulin 



• « • * 



^■•^^p— ^ V V ^^F^ 



m m t*\^ \^ lj KA VA I 1 111 



* Wherever the term "diffusion-extract" is employed, it refers to a diffusion 

 in water of the alcohol precipitate from an aqueous extract of the alga under 

 discussion. 



f The sugar values in this and the following tahles are net, i. e., sugar values 

 for all checks have been deducted. 



t In all the following experiments an amount of sugar below 2 mgms. is 

 designated a "trace." 



