ANNUAL REPORT FOR 1902 OF THE
CONSULTING CHEMIST.

THERE have been during the past twelve months (December 1, 1901, to November 30, 1902), 752 samples sent by members of the Society for analysis, this constituting an increase of 70 over the number (682) sent the year previous.

The leading features of the year, so far as this may be judged from the samples sent, may be put down as: (1) the adoption by the majority of manufacturers of linseed cake of the standard of "pure," as against that of "95 per cent." or other percentage of purity; (2) the extensive introduction of Bombay cotton seed for the making of undecorticated cotton cake; (3) the introduction and subsequent disappearance of a crude form of potash salts (carnallit).

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PURITY OF LINSEED CAKES.

For a long time past the Society has been urging its members, when purchasing linseed cake, to insist upon a simple guarantee of its being "pure," the opinion of the Consulting Chemist to be conclusive as to whether a cake is or is not pure." It has been pointed out over and over again that such a guarantee as “95 per cent. pure " affords no proper security, leaving out of account, as it does, what the nature of the remaining 5 per cent. may be. A linseed cake might, for instance, contain some poisonous seed or material and yet be covered by a "95 per cent. pure guarantee. Further, the existence of a limit of this kind does not tend to the cleaning of the seed as thoroughly as possible, but to the production of a cake that will just comply with the requirement, and if seed is to be paid for on a basis of "95 per cent." it may be taken as certain that there will be no inducement to get it of higher quality, and hence more care in screening the seed is subsequently required. Moreover, it has been pointed out that while, in the case of the uncrushed seed, it is easy enough to pick out mechanically the seeds" other than linseed," yet, after the seed has been crushed into cake and the oil in part expressed it is impossible to say absolutely, by either chemical or microscopical means, whether the seed originally used was " 95 per cent. pure" or not.

For these reasons I have always declined to certify to linseed cakes being 95 or other percentage pure, but have

regarded them simply from the standpoint of what experience has told me can, by the use of good seed and proper screening, be reasonably expected in a cake that is to be termed "pure.'

No one suggests for a moment that by "pure" is meant "absolute purity," i.e., the absence of anything-however small in amount-that is not linseed; but it implies what amounts to practical purity, viz. the absence of excessive sand and of any injurious seeds or materials, together with no more extraneous weed or other seeds than would exist in a cake made from seed of good quality and subsequently screened with reasonable care.

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Upon this line I have all along worked, and have advised the members of the Society accordingly, so that it has now come to be very generally understood what a pure" cake is, according to the Society's definition. It has been found, however, more difficult to persuade the "trade to adopt this definition, though it is but fair to mention that when the pronouncement was first made, two firms-the Waterloo Oil Mills Co., Hull, and the Phoenix Oil Mills Co., Liverpool-announced their willingness to guarantee their cakes subject to this definition, and to abide by my decision. Some few other makers, when asked by the purchasers, have likewise sold on this basis, and there has been a virtual, if not generally expressed, concurrence on this point, though the term "95 per cent." still continued to be the accepted one in the "trade." Recently, however, an important step has been taken by the British Oil and Cake Mills, Limited, a body controlling by far the greater number of cake manufactories in this country, who have announced that, as regards the linseed cake made by the firms under their control, they will in future sell, not on the " 95 per cent." basis as before, but on that of "pure," meaning thereby the standard of "pure" as understood by the Royal Agricultural Society of England, and subject to the decision of the Society's Consulting Chemist. It is a matter for great satisfaction that the continued efforts made by the Society have been thus endorsed by the trade, and the benefit to the farming community will be a material one. Any cake sold as "linseed cake" will thus imply that it is a "pure" cake, and not 95 per cent. pure or some other percentage, and cake that cannot be called "pure" must not be sold as linseed cake," but as "oil cake," or under some other name.

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A. FEEDING STUFFS.

1. Linseed Cake.

Taken altogether, I should say that the improvement reported in past years in the purity and quality of linseed cakes has been more than maintained. Now and again I have cakes

Linseed and Cotton Cakes.

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sent me which are distinctly impure, but, on inquiry, these generally turn out to have been offered as "oil cake" and not as "linseed cake." No new form of adulteration has been brought to notice. While there has been this improvement generally as regards purity, it must not be overlooked that a linseed cake may be pure and yet of low quality, owing mainly to extreme pressure in manufacture, the oil percentage being thus largely reduced, as also the consequent value of the cake. The following is an instance in point :

This cake cost (in March, 1902) 77. 17s. 6d. per ton, delivered at Thetford, Norfolk, and must be called decidedly dear.

2. Undecorticated Cotton Cake.

Undoubtedly the prominent feature in connection with this cake is the introduction, and that to a very large extent, of cake made from what is generally termed " Bombay cotton seed." This is seed which has been but very imperfectly cleaned, a considerable quantity of the cotton wool being left attached to the seed, and the resulting cake having a very "woolly" appearance in consequence. There is considerable

difference between cotton seed of various kinds and grown in different countries, in respect of the relative ease with which the cotton can be removed from the seed in the operation of "ginning." Egyptian seed has been always considered the best in this respect, and contracts often stipulate that the seed shall be Egyptian cotton seed. Objection has been taken, and I think rightly, to cakes that are "woolly." woolly." I have watched this point for several years, and have not unfrequently had instances brought to my notice in which injury has been done to stock by the use of cotton cake made from badlycleaned seed. The cotton fibres left attaching to the seed are liable to collect the pieces of husk, and these have a tendency to form together in masses and produce irritation of the bowels, and, in extreme cases, stoppage. I have had specimens sent me of such collected masses where death of stock has actually occurred, and the matting together of the cotton fibres and the husk is plainly observable.1 It is now asserted that there is

1 See Journal R.A.S.E., Vol. 54, 1893, page 807; and Vol. 58, 1897, page 728.

no danger from the use of such cake, but that cattle, both in India and America, have been fed on the woolly seed without any harm resulting. Some have even gone so far as to say that the cotton wool possesses an advantage, in that it contains a certain quantity of phosphoric acid!

Vigorous efforts have been made, in consequence, to put on the market cotton cake made from this imperfectly-cleaned seed, and these have to a large extent succeeded, for "Bombay cotton cake" is now generally an article of sale. Though frequent representations have been made to me as to the harmless character of this cake, I still do not see my way to regard its use as other than risky. I have myself seen cattle feeding on the uncleaned seed in India, but I have seen them also eating many a coarse indigestible food which our highlybred stock in England would or could not eat, and the conditions both of country and surroundings are not analogous. Further, though I am free to allow that in many cases this cake has been used in this country with impunity, there are yet instances which have been brought to my notice where harm has been done, and the use of the cake bad to be given up, so I must still hold that persons who use it do so at their own risk.

But there are other features of the case, and the most important is that, though this cake is offered at a temptingly lower price, I cannot see that its use is economical as compared with that of good cotton cake made from well-cleaned seed. Other objections I have are that the cake, as a rule, contains excess of sand, and that it is almost invariably “dosed" with "chemicals" of a preservative nature, in order to maintain a bright and fresh appearance of the cake. Borax is the substance generally employed for this purpose.

I have made frequent determinations, by mechanical separation and subsequent washing, of the husk and wool as distinguished from the meal or genuine feeding material contained in the cake, and so high is the amount of the former in the Bombay cake as compared with that in cake made from wellcleaned seed, and so inconsiderable is its value as food, that I cannot see how, regarded even from the monetary point of view, and apart from any question of risk in its use, the cake can be economical to purchase. It should be mentioned that in an ordinary chemical analysis of such a cake the actual amount of "fibrous material does not appear, a good deal of this being soluble in the acid and alkaline reagents used to get at the amount of "woody fibre"; but, by separating the meal from the fibrous matter mechanically, one can get a much better idea of the comparative values of two cakes, the one from cleaned and the other from uncleaned seed. I have applied

this test to a large number of samples, and, to select a few cases, I append the following:

All of these samples contained borax as a preservative. Determinations, similarly made, of coarse husk and fibre in cotton cake made from well-cleaned seed have given only from 10 to 20 per cent., while the sand has only been about 25 per cent.' When, therefore, we consider that there may be, roughly, from three to four times as much coarse husk and cotton fibre in these woolly cakes as in a good one, it would seem that the reduction of price-which amounts to about 17. per ton, as a rule-as compared with the price of Egyptian cotton cake, is dearly obtained.

Lastly, I must renew my protest against the use of "chemicals" in cattle foods. This is, in my opinion, a reprehensible practice, and one which would soon disappear if purchasers would only insist upon the cakes, &c., they buy being pure and free from it, for I certainly consider the intentional addition of borax or other preservatives as an impurity. If food is good and sound it needs no preservatives, while they, on the other hand, may be used to obscure the inferior quality or keeping powers of cattle foods, and also in order to give to cakes a fictitiously bright and fresh appearance. Borax, it is recognised, does no good, and may, if used in excess, do harm to digestion, and if the use of this and other preservatives is allowed there is no limit to the extent to which it may be employed. The best thing is to buy good, sound, natural food, and to object altogether to "chemicals" being added to it.

3. Decorticated Cotton Cake.

It is still to be regretted that it is difficult to get a really good and soft cake of this class, for I am convinced that there is no better and cheaper cake, whether considered in respect of feeding or of manurial value. The practice of grinding up hard cakes and remaking them into softer ones, continues, and, though I would prefer to have the natural cake, if fairly soft,

1 See Journal R.A.S.E., Vol. 53, 1892, page 787.