1915] 



DAVIS — ENZYME ACTION IN MARINE ALGAE 775 



the diastase and maltase of the barley grain, or they may only 

 arise when there is food transformation and translocation, as 

 in germinating seeds. However, in the light of such possi- 

 bilities of association, it is worth while to call attention briefly 

 to some of the work that has been done on the chief storage 

 products of the algae. 



The carbohydrates have been more worked over in this 

 respect than has any other chemical group, but much confusion 

 still exists regarding their exact status in assimilation. Much 

 of the study has been on the cleavage products, obtained by 

 acid hydrolysis, of undetermined carbohydrates. These, how- 

 ever, are not a true index of the distribution and more re- 

 stricted chemical nature of assimilable carbohydrates in the 

 living plant ; one must look rather to the work of those who 

 have limited themselves to the isolation and determination of 

 unaltered carbohydrates. 



CHLOROPHYCEAE 



Polysaccharides.— Nageli ('63) reported " spharokristalle " 

 in Acetdbularia which Leitgeb ( '87) later showed were inulin. 

 The former worker also demonstrated the presence of this 

 carbohydrate in various members of the Dasycladaceae. 

 Kiister ('99) has more recently found characteristic crystal 

 formations in Derbesia and Bryopsis which, from the many 

 reactions they gave, appear to have been inulin. Famintzin 

 ('67) and Krause (70) worked on the effect of light on 

 starch formation in Spirogyra, and within recent years, Tim- 

 berlake ('01) has contributed observations on the starch of 

 Hydrodictyon. Oltmanns ('05, p. 147) speaks of starch ac- 

 cumulation in the Conjugates, Volvocales, Ulotrichcdes, 

 Charales, Siphonocladiales, and some of the Siphonales. He 

 considers it the first visible product of assimilation, but 

 thinks that it may also function as a reserve. Starch in the 

 marine forms seems to be quite widely distributed. In the 

 work of Arber ('01), to which reference has already been 

 made, starch accumulation in the tissues of Viva, Cladophora, 

 and Enteromorpha was easily demonstrated by means of 

 iodine. Swartz (11) isolated starch from Viva but was 

 unable to prove its presence in Enteromorpha, a closely re- 



