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Obituary Notices of Fellows deceased. 



Much of Adrian Brown's work was in criticism, of Pasteur's findings,, 

 especially the great Frenchman's conclusion that fermentation was life without 

 air; he thought that he had proved the contrary. He studied the effect of 

 alcohol and found that it greatly retarded the reproductive growth of yeast ; 

 also the effect of carbon dioxide but came to the conclusion that, as it had no 

 greater influence than hydrogen and as there was a much larger increase in 

 presence of air, that the repression of growth was due to exclusion of oxygen. 

 He was, therefore, led to favour the conclusion that reproductive growth of the 

 yeast cell, under ordinary anaerobic conditions, is determined by the amount 

 of oxygen at the disposal of the organism prior to the commencement of 

 reproduction. 



Eecently, however, Slator, working in the laboratory of Messrs. Bass and Co., 

 has adduced proof that not only has carbon dioxide a greater influence 

 than has been supposed on the activity of the yeast organism but also 

 that oxygen is not required for reproductive growth of the cell — thereby 

 upholding both a common opinion of carbon dioxide and Pasteur's view as to 

 oxygen being unnecessary. 



It remains to consider what is undoubtedly his most remarkable work — 

 that on diffusion into the barley corn, noteworthy both on account of the 

 beauty and delicacy of the method he developed and the significance of 

 the results. Having eyes to see as well as an inquiring mind, he was led to 

 take special notice of the blue layer just below the skin in certain varieties 

 of barley. Desirous of finding out what happened, in the malting process, 

 when barley was steeped in water, as it is during the preparation of malt, 

 also what would be the influence of impurities in the water, he first studied 

 the behaviour of dry barley-corns in water and then in various solutions. 

 He saw that in blue barley he had a perfect mechanism for the quantitative 

 study of diffusion phenomena. The blue layer furnished the discriminating 

 membrane ; the finely granular mass of starch within the corn served to 

 attract water into the grain. By placing a set of weighed corns in water 

 and at intervals removing them and determining the increase in weight, at 

 various temperatures too, the rate at which water entered was easily ascer- 

 tained. The variation in the rate at which it accumulates in the grain, as the 

 temperature is raised, was in agreement with that at which the vapour 

 pressure of water rises when this is heated. 



A similar tale is told by solutions of most salts and of substances such as 

 the sugars — these all have vapour pressures lower than that of water and 

 water accumulates less rapidly in barley corns placed in these solutions than 

 if they were in water, the rate depending on the concentration. 



Solutions of the ordinary strong acids and alkalis also give up water 

 to dry barley corns and become concentrated but no acid passes across 

 the discriminating membrane ; the blue colour remains unchanged in all 

 sound corns. 



But weak acids, also weak alkalis, such as ammonia, readily pass through ; 

 moreover, the membrane is penetrable by all chemically neutral substances^ 



