214 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



curious outgrowths to sprout from the stem, and these present a 

 striking resemblance in form to the fructifications of the higher fungi. 

 They consist, however, for the most part of tissue derived from the 

 flowering plant, which bear within themselves the reproductive spores 

 of the fungus. These remarkable structural peculiarities which so 

 often result from the interaction of host and parasite are of the greatest 

 theoretical interest, inasmuch as they emphasize the dependence of 

 form upon chemical constitution, but to pursue this further would 

 take us more deeply into a speculative field of inquiry than is permitted 

 during the few minutes that remain at our disposal. A more im- 

 mediately profitable line of investigation is that which is directed 

 towards the ascertaining of the causes and conditions of immunity, and 

 of the means, whether by breeding or otherwise, whereby immune 

 races may be raised and preserved. The meaning of predisposition, 

 in the various species and varieties, similarly requires to be studied, 

 for it is only when we have rightly understood the causes that we can 

 expect to grapple with the onset of disease with certain success. It 

 is work in which the horticulturist should largely set the problem, 

 which it is the business of the botanist and the chemist to solve. 

 Science and practice are sometimes ignorantly spoken of as though 

 they were distinct, and even antagonistic. A better knowledge is now 

 prevailing, and dispersing this fundamentally wrong conception of the 

 matter. Science and practice are really so closely akin as to be almost 

 interdependent, and the focusing of the joint efforts of such a triad 

 of workers as I have just indicated can only result in good to horti- 

 culture. The extension of the confines of chemistry and botany that 

 must ensue will result in a further increase of our power to direct and 

 control the processes that go on within the living plant. Hence we 

 may with confidence predict that we shall one day bring within the 

 sphere of ordinary practice much that, for lack of knowledge, is still 

 impossible. 



