56 SOME RECENT RESEARCHES IN PLANT PHYSIOLOGY 



hydrolysis. Recently Duggar and Davis (1914) investi- 

 gated the enzymes of Fucus vesiculosus, but could detect 

 none except catalase, which Atkins (1914, 2) had previ- 

 ously located. This poverty in enzymes is very remark- 

 able, for one might reasonably expect to find one capable 

 of splitting carbohydrates. 



CARBOHYDRATES OF THE RHODOPHYCE^. 



In the Florideae the osazone of a simple sugar was ob- 

 tained by Tihomirow (1910). Kylin, however, failed to 

 confirm this, and both he and Kolkwitz (1900) are in agree- 

 ment as to the absence of reducing sugars from the mem- 

 bers of this group examined by them. 



A considerable amount of work has been done upon the 

 nature of riojidfiaBbstarch. 



With iodine the granules give various shades of colour. 

 Thus, Kolkwitz divides the class into those which give a 

 rose-red, as Laurencia and Cystoclonium, and those afford- 

 ing a blue- violet, as do Furcellaria and Delesseria. These 

 modifications of starch are described at length by Oltmanns 

 in his "Morphologic und Biologic der Algen, Bd. II." It 

 may, however, be remarked that some at least bear a strong 

 resemblance to the starch of the phanerogams, in that 

 they are hydrolyzed by dilute acids to yield glucose, and 

 are alsoTapidly acted upon by malt diastase...,. Furcellaria 

 fastigiata was Kylin's source for the material he used. 

 Saiki (1906) found that strong solutions of malt extract 

 failed to digest the carbohydrates of certain commercial 

 food preparations made from Gelidium sp., Porphyra 

 sp., and Chondrus crispus. The influence of the indi- 

 gestible cell wall may perhaps be very appreciable in . 

 these cases. By hydrolysis of similar preparations with 

 acids, Konig and Bettels (1905) were able to identify gajac- _ 

 tose, fructose, and glucose. Whilst from Chondrus crispus 



