AcGUST 1, 1900.] 



KNOWLEDGE. 



3 79 



least the coronal rifts ai-e neither contrast effects nor 

 mere intoi^spaces between bright rays, but are caused 

 bv the interposition of actual dark absorbing matter 

 between ourselves and the general dilTused coronal glow. 

 The form of the corona, iis it .appears to us, is therefore 

 not wholly an emission, but partly an absorption cfTect. 



SOME EARLY THEORIES ON 

 FERMENTATION. -II. 



By W. Stanley Smith, ph.d. 

 (Concluded from page 155.) 



Van Leeiwenhock, 1632—1723, was the first to behold 

 the beautiful cells of the yeast plant, jSacr/iaruiiii^ccs, 

 and he it is who first records their morphology. It is, 

 however, all too certain that Van Leeuwenliock passed 

 away unconscious that his cells were endowed with life ; 

 they were to him " globulis nempe ox quibus farina, 

 mere globules of starchy nature derived from the cereals, 

 wherewith the early brewer prepared his wort. More 

 than a century and a half must perforce roll by ere 

 Caignard de la Tour, in France, and Schwann, in 

 Germany, could proclaim the vital nature of our yeast. 

 The former man of science, observing that it lacked 

 the power of motion, dubbed yeast a plant, and pro- 

 claimed this plant to be the first cause of alcoholic 

 fermentation. Schwann, on the other hand, arrived at 

 the same conclusions, only by a very different method 

 of reasoning. He believed that only mineral poisons 

 were fatal to plant^life, whereas animals succumbed 

 to both mineral and vegetable toxicants. He found 

 his yeast-plant unharmed by strychnine, whilst it 

 succumbed to the presence of arsenic. In order to 

 illustrate the veritable depth of learning achieved by 

 Schwann, we must quote some few of his words. " It 

 is impossible," says he, " to mistake the connection 

 between fermentation and the gi'owth of the sugar-mould, 

 and it is highly probable that the growth of this mould 

 is the cause of the phenomenon attending fermentation. 

 As, however, it is necessary, in order to produce a 

 fermentation, to have a nitrogenous substance present, 

 as well as sugar, it seems that the jjresencc of nitrogen 

 is a condition which must be complied with for the 

 purpose of furthering the development of this plant, and 

 hence, that the plant itself contains nitrogen." These 

 last words may be read in connection with those of an 

 Italian chemist, Fabrioni, who in 1787 discovered the 

 yeast ferment to be what he termed a " vegeto-animal 

 substance — that is. a body which gives off ammonia 

 when burned, and is similar to the albumen and casein 

 of animals, or the gluten of plants. 



Turn to the dryest of dry-as-dust journals, the 

 Aniialen der I'harmacie, and selecting Volume XXIX., 

 read from page 100, onwards, " When yeast is shaken 

 up with water it appears, if examined under the micro- 

 scope, to consist of infinitely small globules, and of fine 

 threads, unquestionably composed of some kind of 

 albumen. If you place these globules in sugar-water, 

 it becomes evident that they are the eggs of an animal ; 

 they swell, burst, and therefrom issues a minute organism 

 which reproduces itself with astounding rapidity, and 

 by a hitherto unknown method. The appearance of 

 this animal differs widely from any of the six hundred 

 species at present described ; it is like a Beindorf 

 distilling flask, without the condensing tubes. The neck 

 of the flask, which acts as a sucking trunk, is lined with 

 fine hairs, but both eyes and teeth are missing. 

 Stomach, intestines, anus (a small rose-coloured point), 



and urinaiy organs ai'e till developed. At the moment 

 of release from the egg, one can sec the animals imbibe 

 the sugai'-water with great relish, and also witness the 

 passage of the sugar into their stomachs. Digestion 

 follows at once, and alcohol passes from the intestines 

 whilst carbonic acid escapes from the urinary 

 organs. ... If the liquid be boiled, fermentation 

 ceases, because the animals arc unable to live at such 

 high temperatures. Excess of alcohol, sulphurous acid, 

 or any minerid acids, are likewise fatal to these 

 creatures." Thus writes the ribald scoffer, and with 

 diabolical ingenuity explains that, all the sugar being 

 decomposed, these marvellous creatures of his fancy cat 

 one another, " digesting^ everything but the eggs, which 

 pass out once more and furnish material for further 

 fermentation." 



Despite this obvious satire (one wonders how it ever 

 got into the Annalen), the vital theory of fermentation 

 would, in all probability, have been accepted, had it not 

 happened that another giant intellect visited our orb, 

 in the person of Justus von Liebig. It must be related 

 of Liebig that he opposed the vital theory of fermenta- 

 tion, but when he came across the memorable words of 

 Ernst Stahl, he undoubtedly brought the full force of a 

 chemical mind to bear upon them, and so we find the 

 molecular theory of Justus von Liebig is an amplifica- 

 tion of that espoused by Ernst Stahl, extended and 

 fulfilled by some few facts his experiments had taught 

 him. We can thus present the Liebig theories: — The 

 component particles of a decomposing body ai'c in con- 

 stant motion, and this motion is, of a necessity, conveyed 

 from one body (the cause of fermentation) to the sub- 

 stance with which it is in intimate contact {e.g., the 

 dissolved ingredients of the brewers' worts). Liebig 

 exerted his knowledge to the utmost in order to gainsay 

 his opponents, and we can find numerous echoes of his 

 opinions on these matters, interspersed between the lines 

 of sundry volumes, translated, in his early years, by the 

 late Lord Playfair, as well as in the translations of 

 Liebig's works furnished by Gregory and Blyth. It 

 seems passing strange to us that a mere mechanical 

 theory should have taken root, when Caignard de la 

 Tour, Schwann and Turpin, had spoken ; but such it 

 was, and until Pasteur had dashed their idols to the 

 ground, a process further effected by Tyndall and Huxley 

 in later years, men scoffed for the most part at Turpin's 

 remarkable words. They run thus, and we will accept 

 them as truth until convinced to the contrary : " Vege- 

 tation as cause, and fermentation as effect, are two 

 things inseparable in an act of sugar decomposition." 



Berzelius, who, said Prof. A. W. Williamson, " had 

 been for a lengthened period the one great man in the 

 domains of inorganic chemistry," and who himself de- 

 clared he had made his greatest discovery in unearthing 

 apothecary Scheele, laid siege to both the theories of 

 Schwann (vital forces) and Liebig (mechanical forces), 

 and steered his way through the mudbanks of con- 

 troversy by declaring the characteristics of yeast to be 

 but the natural attributes of an amoi-phous precipitate. 

 Also one Ehrenbcrg declares that many amorphous 

 deposits may be observed in wreath-like forms, a bare 

 initial fact revealed by hasty microscopic peeping. The 

 Swede, Berzelius, did, of a surety, endow his amorphous 

 precipitate with certain catalytic forces, and we find, in 

 the pages of Puggemlorfs Annalen, a well-known man, 

 called Mitscherlich, came to somewhat like conclusions. 

 He, Mitscherlich, describes his force as that of contact, 

 and quotes, with due erudition, the mysterious action 

 of platinium sponge on hydrogen per-oxide. And yet 



