538 



THE SOUTHERN PLANTER. 



From the British Farmers^ Magazine. 



Vegetable Physiology. 



Professor Henfrey of King's College, Lon- 

 don, delivered before the Weekly Council of 

 the Eoyal Agricultural Society of England the 

 following lecture on Vegetable Physiology, in 

 reference to the kinds, races, and organs of 

 plants: 



Mr. President and Gentlemen : 



In preparing to execute the task with 

 which you have honored me, I felt consid- 

 erable difficulty from the peculiar circum- 

 stances of the case. The occasional lec- 

 tures which have been delivered in this 

 room have been for the most part given 

 with a view to promote practical agricul- 

 ture, and they have had a more peculiar 

 interest here from the circumstance that 

 these experiments have generally been 

 undertaken at the instigation of the Soci- 

 ety. N*ow, scientific men, called upon at 

 short notice, are not always in a position 

 to furnish new facts or new conclusions, 

 or to bring forward series of researches 

 which are capable of practical application. 

 In my own case, my recent work has been 

 devoted especially to subjects whose ap- 

 plication to science, or whose relation to 

 science is at present remote, and in fact 

 to subjects which are so abstract that they 

 scarcely admit of popular treatment : I 

 was therefore thrown more on the general 

 subject. Here again a certain difficulty 

 met me in the circumstance that vegeta- 

 ble physiology may be said to be still in 

 its infancy. Hence it is in possession 

 only (Jf a few well-established generaliza- 

 tions, and these are too well knowm and 

 too commonplace to form the subject of a 

 lecture ; while the objects of its present 

 activity consist chiefly of questions still in 

 a state of debate, overloaded with unclass- 

 ed, unsatisfactory, and even contradictory 

 evidence, the attempt to discuss which 

 could only have led to a kind of contro- 

 versial thesis. It appeared to me, there- 

 fore, better, especially in consideration of 

 circumstances to which I shall presently 

 allude, to occupy your time w^ith a few^ il- 

 lustrations of the nature and objects of the 

 science of vegetable physiology itself, se- 

 lecting these illustrations, as tar as possi- 

 ble, from departments of the subject which 

 either do at present or hereafter may ad- 

 mit of a practical application. The cir- 

 cumstance to w^hich I have just alluded as 



especially influencing me in the tendency 

 or the direction of agricultural physiology 

 of late years — the tendency which rather 

 leaves vegetable physiology, properly so 

 called, in the back-ground. Jf we look 

 back for a few years at the literature of 

 agricultural science, we find that the 

 works which have made most impression, 

 those which have been most valuable, and 

 are best known, have been written by 

 chemists. I need scarcely allude to the 

 works of Liebig and Mulder ; even in the 

 writings of Boussingault, and of Lawes 

 and Gilbert, vegetable physiology, proper- 

 ly so called, has been recognised ; still the 

 vital qualities of plants have been rather 

 looked upon as secondary considerations 

 than as primary. The chemistry of the 

 subject has been that which has principal- 

 ly occupied attention. Far from com- 

 plaining of this, far from regarding it as a 

 mistake, I regard it as desirable, inevita- 

 ble, if we would make secure progress, 

 because vegetable physiology does really 

 depend upon chemistry for some of its 

 most important materials. Vegetable phy- 

 siology is not merely organic chemistry; 

 but organic chemistry is required to ad- 

 vance to a certain degree of perfection, 

 before we have the material upon which 

 vegetable physiology, properly so called, 

 can work. It is hardly necessary to re- 

 mind you of the views which have been 

 entertained by those who have pressed 

 the chemical theory of physiology too far, 

 with the notion that the life of plants or 

 animals consisted merely in a succession 

 of chemical changes. Such a view can 

 only bo entertained by those who take an 

 extremely one-sided view of the subject. 

 The old illustration of the duck's egg ami 

 the hen's egg are sufficient to showjhat 

 there is something more than chemistry 

 in the diff*erence of species, and the same 

 argument may be carried throughout all 

 the details of life, throughout the whole 

 phenomena of organization. Chemists 

 W'ill scarcely be able to distinguish, by any 

 means belonging exclusively to the che- 

 mist, between the germ of the hen and 

 I the duck; but in those germs, undistin- 

 jguishable from one another, lies the ener- 

 gy which results in the product of a total- 

 jly different organization. The line of ar- 

 gument thus illustrated shows at once that 



^e must, in order to cultivate vegetable 

 physiology, advance a step beyond the 



