works have been effected. The example here furnished by Sir Thomas Hesketh might judiciously be followed by many, with advantage to themselves and to the community.

I cannot conclude this report without acknowledging the valuable assistance which has been freely afforded me by the late Mr. Boosie and Mr. Porter, his assistant, and for which I have much pleasure in now tendering my thanks.

February 28, 1852.

XII. On the relative Nutritive and Fattening Properties of different Natural and Artificial Grasses. By J. THOMAS WAY, Consulting Chemist to the Royal Agricultural Society of England.

Ir is very generally known to those who have interested themselves in the history and progress of agriculture in this country, that at an early period of the present century the Duke of Bedford, impressed with the importance of ascertaining, so far as possible, the relative productiveness of different kinds of grasses, and also their relative nutritive value for the feeding of animals, set on foot a series of experiments at Woburn to determine these points. To Mr. George Sinclair the conduct of this investigation was deputed; and to this day Mr. Sinclair's excellent work, embodying the results that were obtained, remains the text-book on the grasses.

Mr. Sinclair's method of procedure was simple enough. He had two questions to determine: the first of these being the relative productiveness of different grasses, or, in other words, what quantity of each might be grown on a given area of soils of different qualities and capabilities. To determine this point, Mr. Sinclair had recourse to the obvious method of growing the different grasses in plots of a definite size, and carefully weighing the produce of each.

The second question-that of the nutritive quality of the grasses so grown-required for its solution an expenditure of greater skill; and Sir Humphry Davy was asked to suggest the proper methods.

The plan adopted by Mr. Sinclair, at the suggestion of this illustrious chemist, was also very simple. A given weight of the grass, either in its natural state or after being dried, was submitted to the action of hot water till all the soluble parts were taken up. The liquid was then separated from the undissolved woody matter by filtration, and carefully evaporated to dryness.

The dry product thus obtained was taken as the measure of the nutritive matter of the specimen examined.

In this way the greater number of the true grasses and other plants found in or suitable to pastures was carefully examined, and the results were published, as before stated, in Mr. Sinclair's work. There can be no doubt that this method of finding the nutritive matter of the plants afforded data which could not fail to be of value to the intelligent agriculturist, and that it was the best which the state of science at that time could offer, or which, with a moderate outlay of labour, was possible, is sufficiently guaranteed by the name of the great chemist who suggested it.

But chemistry and physiology have made gigantic strides since that time. We have learnt to separate and identify the chemical principles of which plants are made up, and their composition and properties have been intimately studied. Physiology, on the other hand, has taught us to a considerable extent the part which these principles play in the nutrition of animals. It has shown us that from one is formed flesh, from another fat, whilst to others, again, is allotted the office of supporting respiration and producing animal heat. It is not meant that science was entirely at fault on these points at the period in question, but there can be no doubt that the greater part of our present knowledge of the subject is of a much later date.

It is, therefore, not to be wondered at, that, with increased knowledge of the offices or functions of vegetable principles in relation to animal life, we should feel the want of a more correct acquaintance with the distribution of those principles in different plants; and it has been long evident to all who have paid any attention to these subjects, that Mr. Sinclair's determinations of nutritive equivalents for different grasses, however valuable they were at the time when they were executed, are quite unsuitable to our present more advanced stage of knowledge. This is so obvious a fact, that it would be almost unnecessary to occupy the pages of the Journal and the time of the reader in discussing it, were it not that I may at the same time show more plainly the grounds upon which the examination which it is the object of this paper to describe has been based.

It may be shortly stated that modern chemistry has divided the principles of plants into two great classes—the one including all those vegetable principles which contain nitrogen; the other comprising those which are destitute of this element.

The nitrogenous principles are essentially alike in composition, but differ somewhat in properties; they are known as vegetable albumen, casein, legumen, &c.: the first of these is soluble in cold water, but coagulates, and becomes insoluble when the water is boiled; the two last are insoluble in water either hot or cold.

The class of non-nitrogenous principles, omitting those which possess no general importance to our present purpose, includes woody fibre, starch, gum, sugar, mucilage, pectic acid, &c., together with different oily or fatty matters. Many of these are soluble in water, as sugar, gum, &c., whilst woody fibre, pectic acid, and starch, are insoluble in cold, and the two former even in hot water.

It is now almost universally conceded that the nitrogenous principles in plants are assimilated, or adopted as it were by the animal economy with little alteration, being, by processes that are easily conceived, converted first into blood, and then into flesh and muscle, all of which they so closely resemble in composition and properties. Little is known as to the relative adaptation of these different substances for assimilation into the animal bodywhether vegetable albumen or vegetable casein, for instance, is more susceptible of conversion into flesh; and for the present, at least, we must be content to regard them in a general way as equally valuable in this respect. But this much is known, that the presence of members of the nitrogenous class is essential to the composition of nutritive food, and that starch or sugar alone is quite unfitted to support, much less to increase, the animal frame. On the other hand, the class of non-nitrogenous substances is equally necessary for the support of respiration and animal heat, and the production of fat. But, whilst physiologists make no great distinction between the members of the fleshforming class, they allot to one set of non-nitrogenous principles the office of supplying the elements of respiration, and to another that of producing fat. Much dispute has existed upon this point -some physiologists asserting that the sugar and even the starch of their food might serve to form fat in animals, whilst others have held the belief that the fat which was deposited in the body must have pre-existed as such in the food. The question seems, however, to have resolved itself into this-that starch, gum, sugar, and oily and fatty matters, may each and all contribute to the respiratory and heat-producing functions; whilst, in the formation of fat, the ready-formed fatty matters take precedence; and, in their absence, first sugar and then starch may be employed for that purpose.

From what has been now said, it will appear that the plan adopted by Mr. Sinclair for the determination of the nutritive properties of the grasses was defective in more ways than one. In the first place, it afforded no kind of information as to the relative quantity of flesh-forming, fattening, and heat-producing compounds existing in the plants; and, in the second, it did not even give a correct idea of the proportion of all these substances

taken collectively-since, with our present knowledge of the properties of the nitrogenous principles, we cannot doubt that treatment with hot water would fail to extract the most nutritive portions of the grass.

As a supplement to Mr. Sinclair's excellent work, and a subject not unworthy of considerable labour, it seemed desirable to examine some of these grasses anew, bringing to the inquiry the aid of more recent physiological principles and the methods of modern chemical research. I freely own, however, that it may be objected to the analyses which are now published, that they do not, any more than those of Mr. Sinclair, put us in possession of the whole truth-such is the case; but, upon consideration, it will be found that the most important points are elicited by them and that they furnish a better means of judging than before existed.

To have undertaken the proximate analysis of so large a series of specimens as the grasses present,-to have separately ascertained the quantity of each different nitrogenous and non-nitrogenous principle they contained, would have been, if not impossible (within any moderate space of time) at least useless, for, as we have seen, our other knowledge of the nutrition of animals is not sufficiently advanced to enable us to make use of such data. But, on the other hand, it was possible to direct our efforts to the acquisition of that class of facts which could immediately be made available in relation to existing physiological knowledge; and with that view I decided upon ascertaining, so far as might be, not the quantity of each vegetable principle present in the different grasses, but that of each class of such principles. The analyses that follow will be found to embrace the following particulars :

1st. The proportion of water in each grass as taken from the field. The necessity for this determination is obvious.

2nd. The proportion of albuminous or flesh-forming principles, including, without distinction, all the nitrogenous principles. 3rd. The proportion of oily or fatty matters, which may be called fat-producing principles.

4th. The proportion of elements of respiration or heat producing principles, under which head are comprised starch, gum, sugar, pectic acid, &c., in fact all the non-nitrogenous principles with the exception of fatty matters and woody fibre. 5th. Woody fibre.

6th. Mineral matter or ash.

It will be observed that some of these particulars are rather of negative than of direct interest; water, for instance, in a plant

is of no value in feeding animals, but its proportion is a necessary element of our calculations, because, with the variations in quantity of moisture, will be corresponding variations, though in the opposite sense, of the real nutritive matter of the plant.

The woody fibre of plants is considered to have no value in a nutritive point of view, except that (which, by the way, is sufficiently important) of giving bulk to the food. Still its determination in this respect was necessary, and was indeed an indispensable step in the process of analysis. The same may be said with regard to the mineral matter or ash.

Under the foregoing heads we have acquired, it is hoped, a very important amount of information-such, too, that it can be immediately brought to bear upon the practical nutritive values of the different grasses.

It is necessary to say a few words in regard to the history of the specimens examined. The grasses were collected for me in the spring and summer of 1849, by Mr. Bravender of Cirencester, to whom my best thanks are due for the execution of so laborious a task. It may give an idea of the labour of such a collection to state that upwards of sixty or seventy specimens were obtained by Mr. Bravender, each individual plant composing the sample of 2 or 3 lbs. weight which was necessary for the purpose of analysis, being picked separately from the. meadows in which they were growing. I have elsewhere, in giving the analyses of the ashes of the grasses, stated my reasons for preferring to take the plants from meadows in which they were growing naturally and healthily, rather than seeking to raise them in one soil and under one set of circumstances which could not be equally favourable to all. Time also was a consideration, and the adoption of the latter plan would have entailed considerable delay.* The grasses were collected, plant by plant, at the time of flowering (except where otherwise stated), and forwarded immediately in tin cases to London for examination.

I shall not trouble the practical agriculturist with a description of processes which would be tedious to him and of no practical advantage; but, for the information of those who may wish to know the methods of analysis pursued, I shall add them in an Appendix to this paper.

To economise space and afford facilities for comparison, the

* The analyses were in great part completed and ready for publication in 1850, but from several causes their appearance in print was delayed-a circumstance which I by no means regret, as it has enabled me to increase the value and extent of the investigation very considerably.