TRANSACTIONS OF SECTION K, 7&5 



molecule of sugar is split up iu that way into alcohol and carbon dioxide, and 

 that the alcohol is the nutritive part of the sugar molecule. Certainly Maze's 

 experiments on the submerged seeds with the plumule exposed above the water 

 are not iuconsistent with that view. Uuclaux has spoken more definitely still 

 on this point, and has said that the alcohol formed becomes a true reserve 

 material to be used for nutriment. 



We have, however, further evidence that to some plants, at all events, 

 alcohol is a food. Laborde has published some researches conducted upon a 

 fungus, Eurotiojisis Gaijoni, which point unmistakably to this conclusion. He 

 cultivated it iu a solution containing only the mineral constituents of IJawlin's fluid 

 and a certain percentage of alcohol, usually from four to five per cent. The plant 

 grew well, formiug little circular patches of mycelium, which enlarged radially 

 as the growth progressed. The mycelium became very dense in the centre of 

 the patches, and the fungus evidently thrived well. As it grew the alcohol 

 slowly disappeared, the rate being about equal to that of sugar in a similar 

 culture in which this substance replaced the alcohol. The mycelium in some 

 experiments was cultivated quite from the spores. Eurotiopsis is a fungus which 

 has the power of setting up alcoholic fermentation in saccharine solutions. Wheii 

 cultivated in these alcohol is accordingly produced, and subsequently used, but 

 the growth of the mould is not so easy under these conditions as when the 

 alcohol is supplied to it at the outset. 



Duclaux has shown that in the case of another fungus, the well-known 

 Aspergillus niger, though alcohol kills it while it is in course of germinatior» 

 from the spore, it can utilise for nutrition 6-8 per cent, when it becomes adult, 

 continuing to grow, and putting out aerial hyphse. Eurotiopsis is more pro- 

 nounced in its liking for alcohol, for it thrives in a mixture containing 10 per 

 cent. ; even if submerged entirely it continues to grow and flourish iu an eight 

 per cent, solution. 



The peculiarity relates only to ethyl alcohol ; methyl alcohol will serve as a 

 nutritive medium for only a little time, sufiicient only for the commencing 

 development of the spores into a mycelium and disappearing very slowly from 

 the culture fluid. The higher alcohols, propyl, butyl, and amyl, not only give no 

 nourishment, but are poisonous to spores. A very small trace of any of them can 

 be used by the adult mould. 



Laborde claims to have established as the result of his investigations that 

 Eurotiopsis normally makes alcohol from the sugar to nourish itself with it, just 

 as yeast makes invert sugar from cane sugar because it is the nutritive material it 

 likes best. Tbe enzyme zymase is present in the fungus and plays the part of an 

 alimentary enzyme. Its consumption lasts twice as long as that of a corresponding 

 weight of glucose ; it can serve twice as long for the nutrition of the same weighti 

 of plant. 



These remarkable results lead us to the consideration of the mode in whick 

 the carbohydrates, and particularly the sugars, are assimilated by the plant. We 

 have held the view that the sugar molecule is capable of entering witis 

 little if any alteration into that of protoplasm. We have found no direct evidence 

 bearing upon its fate. It is possible to detect sugar in the axis of a plant till quite 

 near its growing point. Then the reaction ceases to be obtainable, and we know 

 that assimilation is taking place. But we have still to investigate the steps, no 

 very easy problem to undertake. May it possibly be that it is the alcohol moiety 

 of the sugar which tbe protoplasm takes up, part of the carbon dioxide evolved hy 

 the growing organ being an expression, not of respiration, but of a fermentation 

 preliminary to assimilation ? 



But I feel I have dealt at sufficient length with this question. I pass, there- 

 fore, to consider briefiy another nutrition problem of a rather diti'erent kind. The 

 germination of seeds is a question that might be thought to have been fairly 

 settled by the investigations of the latter half of the last century. We have come- 

 to the conception of the seed as fundamentally a young embryo lying quiescent 

 within its testa, and provided Avith a store of nourishment deposited either within 

 its own substance, or lying round it in the tissues vaguely named endosperm or 



