Critiques and Addresses

t water, or by mixing honey with water-are liable to undergo a series of very singular changes, if freely exposed to the air and left to themselves, in warm weather. However clear and pell

as if it were simmering on the fire. By degrees, some of the solid particles which produce the turbidity of the liquid collect at its surface into a scum,

t it has acquired properties of which no trace existed in the original liquid. Instead of being a mere sweet fluid, mainly composed of sugar and water, the sugar has more or less completely disappeared, and it has acquired that peculiar smell and taste which we

l, possesses the intoxicating powers of the fluid in an eminent degree, and takes fire the moment it is brought in contact with a flame. The alchemists called this volatile liquid, which they obtained from wine, "spirits of wine," just as they called hydrochloric acid "spirits of salt," and as we, to this day, call refined turpentine "spirits of turpentine

elmont, lived in the latter part of the sixteenth and the beginning of the seventeenth century-in the transition period between alchemy and chemistry-and was rather more alche

s cohol speciatim pulverem impalpabilem ex antimonio pro oculis tin-gendis denotat ... Hodie autem, ob analogiam, quivis pulvis te

der, or a very pure, well-rectified spirit." But, by the time of the publication of Lavoisier's "Traité élémentaire de Chimie," in 1789, the term "alcohol," "alkohol," or "alkool" (for it is spelt in all three ways), which Van Helmont had applied primarily to a fine

own to us as "fermentation;" a term based upon the apparent boiling

r plainly derived from, theirs for the scum and lees. These are called, in Low German, "g?scht" and "gischt;" in Anglo-Saxon, "gest," "gist," and "yst," whence our "yeast." Again, in Low German and in Anglo-Saxon, there is another name for

menting substance. Thus "hefe" is derived from "heben," to raise; "barm" from "beren" or "b?ren," to bear up

the fermenting substance is seen in the

the ghosts of the ancient Egyptians were solaced by pictures of banquets in which the winecup passes round, graven on the walls of their tombs. A knowledge of the process of fermentation, therefore, was in all probability possessed by the prehistoric populations of the globe; and it must have become a matter of great interest even to primaeval wine-bibbers to study the methods by which fermented liquids could be surely manufactured. No doubt, therefore, it was soon discovered that the most certain, as well as the most expeditious, way of making a sweet juice f

is due, not to the evolution of common air (which he, as the inventor of the term "gas," calls "gas ventosum"), but to tha

und to be identical with that deadly "choke-damp" by which the lives of those who descend into old wells, or mines, or brewers' vats, are sometimes

us products of fermentation. And finally, in 1787, the Italian chemist, Fabroni, made the capital discovery that the yeast ferment, the presence of which is necessary to fermentation, is what he

be done. The words in which he expresses this conception, in the treatise on elementary chemistry to which reference has already been made, mark the year 1789 as the commencement o

: the quality and quantity of the elements remain precisely the same, and nothing takes place beyond changes and modifications in the combinations of these elements. Upon this principl

rmentation; and it is evident that the knowledge of either of these must lead to accurate conclusions concerning the nature and composition of the other. From these considerations it became necessary accurately to determine the constituent elements of the fermentable substances; and for this purpose I did not make use of the compound juices of fruits, the rigorous analysis of which is perhaps impossible,

ysis of sugar and of the products of

at the expense of the other, so as to form carbonic acid; while the other part, being disoxygenated in favour of the latter, is converted into th

of Chemistry." By M.

ond Edition, 179

mentation by Pasteur, in 1860, proved that this is not exactly true, and that there is a deficit of from 5 to 7 per cent. of the sugar which is not covered by the alcohol and carbonic acid evolved. The greater part of this deficit is accounted for by the discovery of two substances, glycerine a

ermentation have simply undergone rearrangement; like the soldiers of a brigade, who at the word of command divide themselves into the

rving perishable articles of food excited so much attention in France at the beginning of this century. Gay-Lussac, in his "Mémoire sur la Fermentation,"[1] alludes to Appert's method of preserving beer-wort unfermented for an indefinite time, by simply boiling the wort and closing the vessel in which the boilin

"Annales de C

ay be allowed to have free access to beer-wort, without exciting fermentation, if only eff

esence of yeast, rests upon an unassailable foundation; and the inquiry into the exact nature of

de two centuries ago by the patient and painstaking Dutch

revisiam esse censui, constare observavi: vidi etiam evidentissime, unumquemque hujus fermenti globulum denuo ex se

stat aquae calore dissolvi et aquae commisceri; hac, vero aqua, quam cerevisiam vocare licet, refrigescente, multos ex minimis particulis in cere

ek, "Arcana Naturae De

act that yeast had a definite structure, but not the meaning of the fact. A century and a half elapsed, and the investigation of yeast was recommenced almost simultaneously by Cagniard de la Tour in France, and by S

in diameter, and the smallest may measure less than one seven-thousandth of an inch, are living organisms. They multiply with great rapidity, by giving off minute buds, which soon attain the size of their paren

not succeeded in verifying these statements; and my own observations lead me to believe, that while the connection between Torula and the moulds is a very close one, it is of a different nature from that which has been supposed. I have never been able to trace the development of Torula into a true mould; but it is quite easy to prove that species of true mould, such as P

ed that the power which causes the rearrangement of the molecules of the sugar is intimately connected with the life and g

ull of the then novel conception of acids and bases and double decompositions, propounded the hypothesis that sugar is an oxide with two bases, and the ferment a carbonate with two bases; that the carbon of the ferment unites with the oxygen of the sugar, and gives rise to carbonic acid; while the sugar, uniting with the nitrogen of the ferment, produces a new substance analogous to opium. This is decomposed by distillation, and gives rise to alcohol.) Next, in 1803, Thénard propounded a hypothesis which partakes somewhat of the nature of both Stahl's and

somebody who knocks the table, and shakes the card-house down; according to Fabroni, the ferment takes out some cards, but puts others in t

sessed. The general nature of these phenomena may be thus stated:-A body, A, without giving to, or taking from, another body, B, any material

from the bitter almonds. The amygdalin thus obtained, if dissolved in water, undergoes no change; but if a little s

ted Cagniard de la Tour's discovery with no small contempt, and, from that time to the present, has steadily repudiated the notion that the decomposition of the sugar is, in any sense, the result of the vital activity of the Torula. But, though the notion that the Torula is a creature which eats sugar and excretes carbonic acid and alcohol, which is not unjustly ridiculed in the most surpr

mals" and of the manner in which their functions are performed, is given with a circumstantiality worthy of the author of Gulliver's Travels. As a specimen of the writer's humour, his account of what happens when fermentation comes to an end may suffice. "Sobald n?mlich die Thiere keinen Zuc

se it constantly produces, as an essential part of its vital manifestations, some substance which acts upon the sugar, just as the synaptase acts upon the amygdalin. Or it may be, that, without the formation of any such special su

at rapidity. The vinegar plant, which is closely allied to the yeast plant, has a similar effect upon dilute alcohol, causing it to absorb the oxygen of the air, and becom

physique propre, analogue à celui du noir de platine. Mais il est essentiel de remarque

r les Mycodermes," Comp

f its merely physical constitution, it is at any rate possible that the physic

ne, supported by Liebig, according to which the atoms of the sugar are shaken into new combinations, either directly by the Torulae, or indirectly, by some substance formed by them; and, on the other hand, by the Thénardian doctrine, supported by Paste

pon the theory of fermentation. So long ago as 1838, Turpin compared the Torulae to the ultimate elements of the tissues of animals and plants-"Les organ

able investigations into the form and development of the ultimate structural elements of the tissues of animals,

d all living organisms, in the long run, into an aggregation of such sacs or cells, variously modified; and tended t

ks of Torula as a "cell;" and, in a remarkable note to the

t fully and exactly known operation of cells, and represents, in the simple

nalogous to that which a Torula exerts on the saccharine solution by which it is bathed. A wonderfully suggestive thought, opening up view

ding its own life and having its own laws of growth and development, the aggregation being dominated and kept working towards a definite end only by a certain harmony among these units, or by the superaddition of a controlling apparatus, such as a nervous system, this concep

sually formed independently of other cells; but, in 1839, it was a vast and clear gain to arrive at the conception, that the vital functions of all the higher animals and plants are the resultant of t

notion of the fundamental unity of structure of living beings. And, before long, the researche

such a substance is contained in all ferments. Before him, Fabroni and Fourcroy speak of the "vegeto-animal" matter of yeast. In 1844 Mulder endea

ans les tissus végétaux la vue directe où amplifiée nous permet de discerner sous la forme de cellules et de vaisseaux, ne représente autre chose que les enveloppes protectrices, les rése

ag

les tissus des plantes, sont formés des éléments qui constituent, en proportion peu variable, les organismes animaux; qu'ai

les Développements de

ées." i

ce of which to the essential constituents of living animals is so strongly indicated by Payen. And through the twenty-five years that have passed, since the matter of life was first called protoplasm, a host of investigators, among whom Cohn, Max Schulze,

apparently without any knowledge

icle, is enclosed within an inert cellulose membrane, which permits it only to exhibit an internal motion, expressed by the phenomena of rotation and circulation, while, in the former, it is not so enclosed. The protoplasm in the form of the primordial utricle is, as it were, the animal element in the plant, but which is

Protococcus pluvialis," in

roscope, but have taken the trouble to become acquainted with well-ascertained facts and with their history, will not need to be told that in what I had to say "as regards protoplasm" in my lecture "On the Physical Basis of Life," there was nothing new; and, as I hope, nothing that the present state of knowledge does not justify us in believing to be true. Under these circumstances, my surprise may b

still less has he concerned himself with looking at the facts, but contents himself with taking them also at secondhand. A most amusing example of this fashion of dealing with scientific statements is furnished by Dr. Stirling's remarks upon my account of the protoplasm of the nettle hair. That account was drawn up from careful and often-repeated observation of the facts. Dr. Stirling thinks he is offering a valid criticism, when he says that my valued friend Professor Stricker gives a somewhat different statement about protoplasm. But why in the world d

tly published under th

opla

he same life-matter, (2) which life-matter is, for its part, due only to chemistry, mu

ty of the word "same," for a discussion of which I would refer Dr. Stirling to a great hero of "Aufkl?rung", Archbishop Whately; statement number (2) is, in my judgment, absurd, and c

nitely when grown in the dark, in water containing only tartrate of ammonia, a small percentage of mineral salts, and sugar. Out of these materials the Torulae will manufacture nitrogenous protoplasm, cellulose, and fatty matters, in any quantity, although they are wholly deprived of thos

capacity for living without light is exhibited by some other

h diseases are propagated by contagion and infection, in just the same way as ordinary contagious and infectious diseases are propagated. Of course, it does not follow from this, that all contagious and infectious diseases are caused by organisms of as definite and indepen