Herbage studies. I.— Lotus corniculatus , a cyanophoric plant

Abstract

Hitherto little attention has been paid to the individual plants which constitute the herbage of pasture lands and no serious attempt has been made to appraise their quality; this is the more surprising, as it is well known that certain pastures are of special value as grazing lands and that the food value of herbage often differs to an extraordinary extent in different districts and even in neighbouring fields—so much so that it is impossible to fatten cattle on many, if not on the majority, of pastures; moreover, there are marked differences depending on seasonal conditions. It is clear that such differences may be due both to variation in the botanical composition of the herbage and to variation in the composition of individual plants induced by variation in soil and in climatic conditions; at present, however, it is impossible even to hazard an opinion as to the manner in which these and doubtless other factors are operative. Our present difficulty arises from the lack of methods of appraising quality: we are no longer satisfied which determinations of dry matter, digestible matter and albuminoid nitrogen, now that we realise that quality as much as quantity is of importance—that in the case of cattle, as in our own case, a mixed and varied diet is required and that what may be termed the condimental constituents of food are, perhaps, at least equal in importance to those which serve exclusively as building materials or as a source of energy. An increasing weight of evidence appears to be in favour of the view that the vital processes in plants as well as in animals are controlled in greater or less degree by substances of the class we have proposed to designate collectively as Hormones. There can be little doubt, in fact, that it will be necessary to take many factors into account in appraising the value of foods—far more, indeed, than it has been customary to consider hitherto.