786 REPORT— 1902. 



when compared witli the actual problems of present-day life, its struo-g'les, 

 triumphs, and defeats in the conflict for existence waged to-day by every living 

 organism. The importance of the study of physiology as bearing upon the 

 problems of the morphologists has, I need hardly say, been fully recognised by 

 the worliers in that field. I may quote here a sentence or two from the Address 

 of one of my distinguished predecessors, who said at Liverpool, ' There is a close 

 relation between these two branches of biology, at any rate to those who 

 maintain the Darwinian position, for from that point of view we see that all the 

 characters which the morphologist has to compare are, or have been, adaptive. 

 Hence it is impossible for the morphologist to ignore the functions of those 

 organs of which he is studying the homologies. To those who accept the origin 

 of species by variation and natural selection there are no such things as morpho- 

 logical characters pure and simple. There are not two distinct categories of 

 characters — a morphological and a physiological category — for all characters 

 alike are physiological.' 



But apart from the considerations of the claims of vegetable physiology based 

 upon its own intrinsic scientific value and the interest which its problems possess 

 for the worker himself, and upon the place accorded to it as its relationship to 

 morphology, it must, I think, be recognised as being of fundamental economic 

 importance, especially in these times of agricultural depression. For many years 

 now it has been recognised that agriculture is based upon science ; that it 

 involves indeed properly the application of scientific principles to the cultivation 

 of the soil. But when we look back upon what has passed for agricultural 

 science since the alliance between the two has been admitted, we cannot but 

 recognise how lamentably deficient in breadth it has been. The chemical 

 composition of the soil and subsoil has been investigated with some thoroughness 

 in many districts of the country. The effect of its various constituents on the 

 weight and quality of the crops cultivated in it has been exhaustively inquired 

 into, and a considerable amount of information as to what minerals are advan- 

 tageously applied to the soil in which particular plants are to be sown has been 

 acquired. A. kind of empirical knowledge is thus in our possession, in some 

 respects a very detailed one, quantitative as well as qualitative records being 

 available to the inquirer. But elaborate as have been the researches in these 

 directions, and costly and troublesome as the investigations have been, they have 

 been hardly, if at all, more than empirical. Till quite recently the physiological 

 idiosyncrasies of the plants round which all these inquiries centred were almost 

 entirely ignored. No serious attempt was made to ascertain the way in which a 

 plant benefited by or suffered from the presence of a particular constituent of the 

 soil. What influence, for instance, has potassium or any of its compounds upon 

 the general metabolism of the plant ? Does it affect all its normal nutritive 

 processes, or does it specially associate itself with some particular one ? If so 

 which one, and how does the plant respond to its presence or absence by modifying 

 its behaviour ? So with phosphorus again ; hardly any investigation can be 

 made into the nutritive processes of a plant without this element becoming more 

 or less prominent. In some cases the empirical results already referred to show 

 an enormous influence on the crop exerted by soluble phosphates in the soil or 

 the manure applied to it. But what can yet be said as to the role played by 

 phosphorus or by phosphates in the metabolic processes in the plant ? Further, 

 how do different plants show different peculiarities in their reactions to these 

 various constituents of the soil ? For the advance of agriculture the study of the 

 plant itself must now be added to the study of the soil. The fact that it is a 

 living organism possessing a certain variable and delicate constitution, responding 

 in particular ways to differences of environment, capable of adapting itself to a 

 jertain extent to its conditions of life, dealing in particular ways with diiFerent 

 nutritive substances, must not only be recognised, but must be the basis for the 

 researches of the future, which will thus supplement and enlarge the conclusions 

 derived from those of the past, in some respects correcting them, in others esta- 

 blishing them on a firmer basis. 



In pressing upon the younger school of botanists the importance of this 



I 



