■848 REPORT— 1895. 



looking at things. And I think that if anything could have contributed to make his 

 departure happy, it was the conviction that the completion of his work and his 

 •scientific reputation would remain perfectly secure in the hands of Dr. Scott. 



Vegetable Phtsiologt. 



Turning again to the present, the difficulty is to limit the choice of topics 

 on which I would willingly dwell. In an address which 1 delivered at the Bath 

 meeting in 1888 I ventured to point out the important part which the action of 

 ■enzymes would be found to play in plant metabolism. My expectations have 

 been more than realised by the admirable work of Professor Green on the one 

 hand, and of Mr. Horace Brown on the other. The wildest imagination could not 

 have foreseen the developments which in the hands of animal physiologists would 

 spring from the study of the fermentative changes produced by yeast and bacteria. 

 These, it seems to me, bid fair to revolutionise our whole conceptions of disease. 

 The reciprocal action of ferments, developed in so admirable a manner by Marshall 

 Ward in the case of the ginger-beer plant, is destined, I am convinced, to an expan- 

 .sion scarcely less important. 



But, perhaps, the most noteworthy feature in recent work is the disposition to 

 reopen in every direction fundamental questions. And here, I think, we may take 

 -a useful lesson from the practice of the older Sections, and adopt the plan of entrust- 

 ing the investigation of special problems to small committees, or to individuals who 

 are willing to undertake the labour of reporting upon special questions which they 

 have made peculiarly their own. These reports would be printed in extenso, and 

 are capable of rendering invaluable service by making accessible acquired know- 

 ledge which could not be got at in any other way. 



We owe to Mr. Blackman a masterly demonstration of the fact, long believed, 

 l3ut never, perhaps, properly proved, that the surface of plants is ordinarily imper- 

 meable to gases. Mr. Dixon has brought forward some new views about water- 

 movement in plants, which I confess I found less instructive than many of my 

 brother botanists. They are expressed in language of extreme technicality; but, 

 as far as I understand them, they amount to this. The water moving in the plant 

 is contained in capillary channels ; as it evaporates at the surface of the leaves a 

 tensile strain is setup, as long as the columns are not broken, to restore the original 

 level. I can understand that in this way the ' transpiration current ' may be 

 maintained. But what I want to know is how this explains the phenomena in the 

 sugar maple, a single tree of which will yield, I believe, 20-30 gallons of fluid 

 before a single leaf is expanded. 



We owe to Messrs. Darwin and Acton the supply of a 'Manual of Practical 

 Vegetable Physiology,' the want of which has long been keenly felt. Like the 

 father of one of the authors, ' I love to exalt plants ' (i. 98). 1 have long been 

 satisfied that the facts of vegetable physiology are capable of being widely taught, 

 and are not less significant and infinitely more convenient than most of those 

 which can be easily demonstrated on the animal side. How little any accurate 

 knowledge of the subject has extended was conspicuously demonstrated in a recent 

 ■discussion at the Royal Society, when two of our foremost chemists roundly denied 

 the existence of a function of respiration in plants, because it was unknown to 

 Liebig ! 



Assimilation. 



The greatest and most fundamental problem of all is that of assimilation. The 

 Tery existence of life upon the earth ultimately depends upon it. The veil is 

 slowly, but I think surely, being lifted from its secrets. We now know that 

 starch, if its first visible product, is not its first result. We are pretty well agreed 

 that this is what I have called a ' proto-carbohydrate.' How is the synthesis of 

 this effected .P Mr. Acton, whose untimely end we cannot but deeply deplore, 

 made some remarkable researches, which were communicated to the Royal Society 

 in 1 889, on the extent to which plants could take advantage of organic compounds 

 made, so to speak, ready to their hand. Loew, in a remarkable paper, which wUl 

 perhaps attract less attention than it deserves from being published in Japan,' has, 



' Bull. College of Agric. Imp. Univ. Toldo, vol. ii. 



