76 SUMMARY OF CURRENT RESEARCHES RELATING TO 



races of yeasts cultivated on nitrogenous media. Their intention was 

 to test whether Pasteur's dictum, that " Fermentation is life without 

 oxygen," would hold good for other forms than Saccharomyces cerevisice. 

 They experimented with this yeast, and also with 8. Ludwigii and 8. 

 Fombe. The authors find that the co-efficient of respiration depends 

 on the kind of yeast under culture, and also on the substratum ; they 

 find also that fermentation takes place with full aeration, and they have 

 no doubt that alcoholic fermentation is a zymase fermentation. They 

 got a very small co-efficient from S. Pombe cultivated on ammonium 

 phosphate, which indicated the absence of alcoholic fermentation. 



Micro-chemical Researches on some Glucosides and some Vege- 

 table Tannins.* — A. Goris gives a resume of previous work, dealing 

 with the question of the localisation in the cells of the active principles 

 found in plants. He then describes the results of his investigations 

 on the a3sculin and tannin in the horse-chestnut and in Pavia rubra. 

 iEsculin is characterised by the intense blue fluorescence of its watery 

 solution, its solubility in acetic acid and ethyl-acetate, and its intense 

 blood-red coloration after passing successively into concentrated nitric 

 acid and pure ammonia (Sonnenschein's reaction). After discussing 

 the composition, chemical constitution and affinities of resculin, the 

 author studies its localisation in the plant-tissues by means of Sonnen- 

 schein's reaction. He finds that it is especially localised in the epidermis, 

 often also in the sub-epidermal layer, in the endodermis, and in a peri- 

 pheral layer of the pith ; but it also occurs abundantly, though in 

 varying quantity, in isolated cells of the parenchyma of the cortex and 

 pith, in the pericycle and the medullary rays, in the wood and paren- 

 chyma, and the old bast parenchyma. It is absent from the meristem 

 and from dead tissues, the young bast tissue, the wood-vessels, the root- 

 hairs and the embryo. 



Its formation apparently has no direct relation to the action of 

 light ; it appears in seedlings from seeds germinating in the dark as 

 well as in the light, and bears no relation to the chlorophyll-containing 

 cells, but brightly illuminated aerial organs are the richest in the gluco- 

 side. It does not seem to be a reserve-substance, since it makes its 

 appearance in germination as an early result of the utilisation of the 

 reserves in the embryo. However, in the autumn it partly disappears 

 from the leaves, and is found in the bast of the branches, as if it were 

 being carried towards the persistent parts of the plant. 



The chestnut also contains a tannin (ajsculitannic acid) which 

 M. Goris finds in the same organs and in the same cells as tesculin. 

 Moreover, since the latter, although insoluble in alcohol, disappears 

 from twigs when treated with alcohol, and since the alcohol thus 

 obtained yields under proper treatment a quantity of sesculin, the 

 author concludes that the glucoside occurs in the cells, in combination 

 with the tannin, as a tanno-glucoside. 



By similar or analogous methods the author has studied the fustin 

 in Rhus Cotinus, the fraxin in the Ash, the daphnin in Daphne alpina, 



* Goris, Alb. Eecherches miiToehemiqui s sur quelques glucosides et quelques 

 tanins ve'getaux. Thesis. Joanin, Paris. 190:!. Bee alio Bot. Centralhl., xeiii. (1903) 

 pp. 261-3. 



