a geometrical form in the process of the fermentation of wort of malt and vegetable juices. But this does not take place; these substances, on the contrary, separate in the same manner as all those which do not present a crystalline texture in the form of globules, swimming separately, or attached to each other.

"The appearance which they assume, in this instance, has induced certain philosophers to believe that they saw in yeast living organized beings, plants or animalcules, which, for food, assimilate the elements of sugar, and restore it as excretions, in the form of carbonic acid or alcohol. In this manner they explain the decomposition of sugar, and the augmentation of the mass of yeast in the fermentation of malt liquor.

"But this hypothesis destroys itself. In a pure aqueous solution of sugar, the so-called seed disappeared with the plants during fermentation; fermentation takes place, the sugar is decomposed at the same time as the yeast, but no appearance of the production and reproduction of the seed of plants and animals, which these philosophers recognise as the agents of the phenomenon, is exhibited."(Annales de Chimie, lxxi. 187.)

Whether frequent changes of Yeast are necessary or not in the Brewery.

When brewers get out of trim, (technically so

called) or in plainer language, into irregular fermentations, they immediately resort to changes of yeast as the only remedy to put themselves again to rights; such changes, however, are often more detrimental than useful. These irregularities, nine times out of ten, proceed either from tainted worts or atmospherical fluctuations, instead of any failure in the yeast. They cannot, therefore, be immediately remedied, unless by a better process of brewing, or a favourable change of electrical condition.

It often happens that the fermentation takes a favourable turn of this nature before a change of yeast can be had. Notwithstanding this, as effects are often attributed to wrong causes, particularly in the brewery, should the new yeast be used and any improvement follow, it is unhesitatingly ascribed by the brewer to the change, although his own yeast from a former brewing, under similar circumstances, might have acted equally well, or even better. It can even be easily proved that almost any yeast, under proper management, and all other circumstances at the same time favourable, may be brought into the best working trim in the course of two brewings; what use then for changes, unless from a total want of yeast by long cessations from brewing.

In combating this argument, we have been met by the assertion that changes of yeast in brewing are equally necessary as changes of seed for

land; the latter, however, is a process of nature, while the former is an artificial or chemical process, wherein chemistry can supply all possible deficiencies. In corroboration of what has been said, we subjoin one or two letters from respectable brewers, who have been for years following this system of brewing without any occasion to have recourse to changes of yeast, and whose beer will at all times bear a comparison with that of any of their neighbours. Without reference, therefore, to the opinions of other writers on the subject, we have only further to say, that nothing is here stated but what we have convincing proof of, and are prepared to substantiate by experiment.

Dartmouth, 18th January, 1844.

DEAR SIR,-In answer to your query respecting changes of yeast, I have only to say, that so far as I have seen, since pursuing your system of brewing, no change has been wanted,-it is certainly quite unnecessary.

I can easily understand that after any long cessation from brewing, a supply of fresh yeast must be required, but in no other case, if your mode of working be strictly adhered to.

I am, yours truly,

WM. BLACK, Esq.

JOHN BAKER.

Chesham, January 15, 1844.

DEAR SIR,-In reply to yours of the 10th, we are still of the same opinion, that, by your mode of working, a change of yeast is unnecessary, and as a proof of it, we used the same store you first brought with you for more than three years, and the tuns were uniformly healthy and vigorous; but during the last summer, as we were cleansing the brewery, &c., and consequently omitted a brewing or two, we obtained a fresh store, which we are still using with success. Perhaps you will be good enough to forward a copy of your new edition, when ready, and we will remit the amount.

We are, my dear Sir,
Yours, very truly,

Wm. Black, Es.

THOS. AND JAS. NASH.

Marine Brewery, Ratcliff, 9th Jan. 1844. DEAR SIR,-In reply to yours of the 4th instant, we beg to say that we are most decidedly of opinion that changes of yeast are quite unnecessary; in fact, we never have them except we are obliged, which only happens after we have been stopping for repairs.

We feel indebted to you for the compliment you pay to our beers, which we trust will continue to

deserve the approbation of a brewer so well calculated to express an opinion.

Wishing you every success in the publication of the Third Edition of your valuable work, of which be pleased to send us a copy when published,

We are, dear Sir, yours very truly,

WM. BLACK, Esq.,

J. AND W. S. HOLT.

4, Lansdowne Cottages, Islington.

FERMENTATION.

THE process of fermentation has generally been considered by brewers as very mysterious and uncertain, and over which they have no control. This to a certain extent is no doubt true, for the yeasty. heads covering the beer in the gyle-tun during fermentation will assume different appearances according to the fluctuations of the weather, and the seasons of the year. In summer we never see the light yeasty heads in the third change, rising to the fine rocky or alpine appearance which they assume in open frosty weather, nor do the yeasty heads in the fifth change become so close or solid. also affects differently the

Windy or hazy weather appearance of the heads