NOTES ON KECENT RESEARCH. 



195 



apparently not broken up by its action, though these were often oxidised 

 by secretions of the fungus mycelium outside the cell. Arbutin solution 

 was exceptional, for although it was broken up by the action of the 

 mycelium into sugar and hydrochinon, this latter product appeared to 

 destroy the fungus. Helicin was not of much value for nutrition, as the 

 salicylic aldehyde formed in its decomposition became oxidised to salicylic 

 acid, and this had a poisonous action on the mycelium. Salicin, coniferin, 

 saponin, and glycyrrhizin gave similar results. The nutritive value of 

 these bodies, as regards the fungi, is shown by the quantitative analysis 

 of the dry mycelium of Aspergillus Wcntii after five days' growth on the 



following substances : — 



Normal weight on distilled water . . l-QO 



On arbutin solution 0*95 



On helicin 1-60 



On salicin ....... 2*00 



On amygdalin . . . . . .2-90 



On myronic acid, potash solution . . 2*90 



On coniferin solution ..... 3'20 



On Eaulin's nutritive solution . . . 6'00 



The age, previous nourishment, and inherited peculiarities of the mycelium 

 of the same species of fungus may produce quite different results when 

 the fungus is brought into such solutions. — G. F. S..-E. 



Leaves, Transparency of. 



Leaves, Transparency of {Bei. Bot. Cent. bd. 10, ht. 2). — Dr. L. 



Linsbauer has measured the amount of light passing through the leaves 

 of a great number of plants by means of Wiesner's photometric method. 

 The sun leaves and shade leaves of the same plant show great differences. 

 Generally the shade leaves are much more transparent than those which 

 are exposed to the sun. The transparency was least in the cases of the 

 sun leaves of Cornns sanguinea and Cytisus Laburnum, whilst the shadow 

 leaf of the Beech allowed more light to pass through than any of those 

 examined. Perhaps the most valuable part of the paper deals with the 

 effect of hairs, a red colouring of anthocyan, and the chlorophyll itself in 

 diminishing the light passing through a leaf. Thus colourless parts of a 

 leaf will allow on an average 0'320 part of the light to pass through, 

 whilst if chlorophyll is present in the same leaves only O'OoG passes. 

 The tissues absorb 68 per cent., and the chlorophyll 26*4 per cent, of the 

 light. These results were obtained by testing colourless and green parts 

 of variegated leaves. The protections against too strong an insolation are 

 summed up as follows : — 



1. The angle of the leaf to the light which falls on it. 



2. The natural habitat of the plant, e.g. in the shade of a wood. The 

 author records a light intensity inside a Beech wood as 0"0111, whilst at 

 the same time it was 0*333 outside the wood. 



3. Hairs greatly diminish the light passing through. The hairs were, 

 removed from one-half of a young leaf, and the amount of light which 

 passed through this half was 0*027, as compared with 0*014 passing through 

 the uninjured half. 



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