508 TRANSACTIONS OF SECTION K. 



(a) The ascertaining the ingredients of the ash when the plant is calcined, 

 as showing what the plant actually removes from the soil, and the consequent 

 necessity of replacing the loss of these ingredients. 



(b) The relation of moisture and good tilth (i.e., soil kept porous and 

 absorbent by the presence of decayed animal or vegetable matter, or by the 

 use of coarse sand or breeze for clayey soils) to the vigour of the plant. 



(t) The effect of exposure to wind and sunlight. 



It will be understood that vigorous vegetation may be due to abundance of 

 moisture, and that the amount of alkaloid or essential oil may seem greater 

 or less in proportion to the succulence of the foliage, so that dwarfed growth 

 may be mistakenly supposed to indicate a higher percentage of either alkaloid 

 or essential oil. But it must not be forgotten that, unless the conditions for 

 healthy growth are attended to, the plants soon become a prey to disease, and 

 what is apparently gained in produce is lost in the expense of repeated replanting 

 of the ground necessitated by disease. 



(cl) Another point is the selection of particular individuals for improvement 

 of the species. In a field of cultivated herbs there will always be some that 

 show more vigorous growth, deeper green colour, and an aspect of good health. 

 These plants should be selected for analysis to see if their alkaloidal value is 

 different from or superior to the average amount, and the seed of the fi^rst- 

 developed capsules of healthy and vigorous plants should be saved for propaga- 

 tion. The conditions of the soil in the spot where these particular plants have 

 grown should be recorded. 



(e) Yet another point is the observation of various forms, varieties, or hybrids 

 that occur under cultivation, and their separate cultivation for experimental 

 purposes. It is these that have much to do with success. 



Thus the Japanese menthol plant occurs in several varieties. The first that 

 was imported into this country did not yield anything like the percentage of 

 menthol that the Japanese stated was to be obtained, and it is only lately that 

 the best variety has been brought to Europe, i.e., the kind that yields the full 

 amount of menthol. 



The English peppermint plant yields the highest-priced oil that is obtainable 

 in any country, and I have shown ' that this is due to the fact that the French 

 and American plants belong to different varieties of Mentha piperita from the 

 Ensrlish plant, and that the Chinese and Japanese belong to another species. 



The best variety of Angelica in cultivation is grown in Saxony, apparently 

 in micaceous soil, and the most highly prized caraway is grown in the North 

 of Russia. 



These might be experimented with in this country to ascertain if, under 

 conditions found or obtainable here, these varieties would retain their 

 peculiarities. 



There are about twenty-four varieties of Aconitum NapeUus, but these have 

 never been separately cultivated to ascertain which is the best variety for use 

 in medicine. 



The chamomile needs similar experimentation as regards its volatile oil. 

 There is a variety of Anthemif! noLilis var. b. floscula which has a specially strong 

 odour, but it has not, that I am aware of, yet been cultivated for the oil, 

 although it might prove superior to any of the forms under commercial 

 cultivation. 



The ordinary double-flowered chamomile easily reverts under cultivation to 

 the single form, but the conditions that cause it and the means of preventing 

 it have not, I believe, as yet been published. 



I will not at present refer to the foreign cultivation of medicinal plants, 

 save to allude to the fact that several important plants, such as the Siam benzoin 

 tree, the insect-powder plant, and Ihe best Chinese rhubarb plant, deserve the 

 attention of our Colonies. 



Sir Sydney Olivier, Secretary of the Board of Agriculture and Fisheries, 

 observed that the problem of supplying raw materials for drugs during the early 

 part of the war had had to be dealt with as a matter of emergency, and the 

 co-operation of all 7Dersons who are willing to help in it had been sought far 

 and wide. Such voluntary and unorganised effort, however, could not suffice to 



' Perfumery and Essential Oil Record, vol. iii., p. 10. 



