[Vol. 2 



808 ANNALS OP THE MISSOURI BOTANICAL GARDEN 



to a lesser extent. Glycogen, which is very generally 

 hydrolysed by diastase, is here decidedly less readily attacked 

 than the other polysaccharides. This would seem to indicate 

 that we are dealing with a distinct enzyme, one that might be 

 placed in the same category with dextrinases. These latter 

 always occur with the diastases but are held by many workers 

 to be distinct. 



Some of the substrates tested for hydrolysis do not, as far 

 as we know, occur in the plants investigated. This is true of 

 sucrose, lactose, and inulin. However, although this might 

 reconcile us to the failure to find their specific enzymes, it does 

 not argue conclusively against such enzymes being formed. It 

 is well known that tissues do form ferments that have no de- 

 tectable substrates upon which to act — the rennen of the 

 bird's stomach and the urease of the Soja bean being notable 

 examples. Inulin, as pointed out previously, does occur in 

 certain " greens," as in Acetabularia and members of the 

 Dasycladaceae. Unfortunately, none of these forms were 

 available for investigation. 



The absence of lactase and sucrase is not so significant as 

 is that of maltase. It is very generally considered that in the 

 plant, as well as in the animal organism, poly- and disac- 

 charides must be hydrolysed to simple sugars before assimila- 

 tion can take place. It is hardly possible that the algae are an 

 exception to this general rule and yet it is difficult to account 

 for this important negative result. It is known that inhibit- 

 ing agents do not affect all enzymes alike, and it may be here 

 that if such agents are liberated on the death of the cell, the 

 maltase might prove more sensitive to them than the other 



carbohydrate enzymes. According to the findings of Kyi in 

 ('13), both dextrose and fructose have been demonstrated in 

 the tissues of Ascophyllum, Fucus, and Laminaria, but in ex- 

 tremely small quantities. These results would tend to con- 

 vince one that an enzyme giving rise to them is probably 

 present in the algal cell. 



Such carbohydrates as galactans, pentosans, and mannans, 

 are very frequently met with in the algae and are potentially 

 capable of being split to assimilable sugars. That they are 



