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782 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Kylin (’14) and others have also demonstrated pectin-like 
compounds forming the middle lamella in various members of 
the F'ucaceae. These exist as the calcium salts of pectic-like 
acids which Kylin designates ‘‘Fucinséure’’ and ‘‘ Algin- 
saure.’’ 
PHYSIOLOGICAL SIGNIFICANCE OF ALGAL SLIME 
It is seen that algal slime is made up chiefly of the an- 
hydrides of hexoses and pentoses—carbohydrates that must 
be broken down to simpler form before assimilation by the 
plant would be possible. Two questions naturally arise: (1) 
Do the algae concerned form enzymes that will hydrolyse these 
highly condensed carbohydrates to assimilable form? (2) 
Does the slime itself arise through the breaking down of the 
hemicelluloses of the cell wall through enzymic or other 
causes, or does it represent a final stage in the condensation 
of those hemicelluloses? 
Algal slime as a reserve product.—Galactanases and man- 
nases have been demonstrated in the phanerogams and in the 
fungi by Bourquelot and Hérissey (’99), Griiss (’02), and 
Hérissey (’03). The last worker especially has clearly shown 
the distinct role that galactans and mannans may play as re- 
serve products in the tubers of the Orchidaceae and in many 
of the Leguminoseae. It is significant that Gran (’02°) was 
able to isolate a marine bacillus, B. gelaticus, that acted on 
part of the constituents of agar-agar to give a reducing sugar. 
From the standpoint of a possible symbiosis it would be in- 
teresting to know if this organism has the ability to fix free 
nitrogen. Saiki (’06) experimented with a number of algal 
and lichen preparations containing a large proportion of 
carbohydrates as galactans and pentosans, and concluded that 
the latter could not be transformed into sugars readily by 
carbohydrate digesting enzymes of animal origin and scarcely 
more so by the vegetable enzymes, either of the higher plants 
or of bacteria. 
Still less is known of the digestion of pentosans by the 
higher plants. Schone and Tollens (’92) found no decrease 
in the amount of pentosans during germination and conclude 
