NOTES 179 



der dauernden Garthatigkeit auf den Charakter der Hefe, Weinbau u. Weinhandel, 

 1895, Nos. 25-27. [But see also A. Brown, Fermentative Power, Centr. f. 

 Bakt. u. Paras., 2. Abt., vol. iii. 1897.] 



110. (p. 133). The most important works on the theory of fermentation are: Traube, 



Theorie der Fermentwirkung, Berlin 1858 ; Pasteur, Etude sur la biere, 1876, 

 chap. vi. : Theorie physiologique de la Fermentation, first announced 1 861 

 (note 31) ; Naegeli, Theorie der Gahrung, Munich 1879. For intramolecular 

 respiration see text-books of physiology. The metabolism theory, which is 

 merely an expression of facts free from speculation, has not yet been carefully dis- 

 cussed nor considered in the light of the explanation afforded by other theories. 



111. (p. 134). H. Buchner'S statement (Die Bedeutung der aktiven loslichen Zell- 



produkte fvir den Chemismus der Zelle, Munch, mediz. Wochenschr. 1897, 

 No. 12) that an extract (pressure extract) of yeast free from cells can split 

 up sugar into alcohol and C0 2 is too incomplete to upset existing theories. 

 Such a revolutionary statement ought to be supported by chemical analyses, 

 but these have not been given. In the two papers by Ed. Buchner also 

 (Alkoholische Gahrung ohne Hefezellen) solid proofs of the existence and 

 activity of the ' Zymase ' (the alcohol-forming enzyme of the yeast cells) are 

 wanting. In these papers there is a slight attempt at analytical evidence : the 

 gas is calculated as C0 2 , and in two instances the alcohol was determined (Ber. 

 d. deutsch. chem. Ges. 1897, pp. 117 and 1 1 10). Further communications of 

 Buchner (Ber. d. deutsch. chem. Ges. 1897, p. 2668 ; 1898, pp. 200, 209, 568, 

 1084, 1 531) might seem to support his views more strongly against the objec- 

 tions raised, had not Abeles (ibid. 1898, p. 2335) recently shown that the amount 

 of the poisons added to the extract was much too small in proportion to the 

 amount of yeast from which the extract was obtained. The fragments of 

 protoplasm in the extract would accordingly not all be killed, and might well 

 give rise to the fermentative action of the extract, which would be quite inactive 

 when sufficient amounts of poison are present. BUCHNER'S observations have 

 shown that the pressure-extract of yeast (free from uninjured cells) speedily sets 

 up active fermentation in sugar solutions. But further researches are necessary 

 to show whether a genuine Enzyme (Buchner'S 'Zymase') is the cause of the 

 fermentation, or whether it is not rather due to the pressure-extract itself, which 

 is indeed nothing more or less than a concentrated infusion of protoplasm 

 squeezed out of the cells and preserved, as it were, in its own juice. 



112. (pp. 103, 134). MlQUEL, note 71, and Sur le ferment soluble de l'uree, Comptes 



rendus, Paris 1890, vol. iii. Urase decomposes at 5o°in from three to four hours, 

 at 75° in a few minutes, at 0° it will keep in bouillon for weeks. The optimal 

 temperature is said to be 5o°-55°. The urase formed in five days by Uro- 

 bacillus Scliilzenlergii in one litre peptone bouillon converts at 37° thirty-five 

 grams of urea into carbonate of ammonia. 



113. (p. 138). Kornauth, Ueber das Verhalten pathogener Bakterien im lebenden 



Pflanzengewebe, Centralbl. f. Bakt. xix. 1896; Kaspareck and Kornauth, 

 Ueber die Infektionsfahigkeit der Pflanzen mit Milzbrandboden, Archiv f. d. 

 gesamte Physiol, vol. Ixiii. 1896. 



114. (p. 138). Frank and Kruger, Untersuchungen iiber den Schorf der Kartoffeln, 



Zeitschr. f. Spiritusindustrie 1896 ; Rathay, Ueber das Auftreten von Gummi 

 in der Rebe und iiber die ' Gommose bacillaire,' Jahresb. u. Programm der 

 k. k. onologischen u. pomologischen Lehranstalt Klosterneuburg, Wien 1896; 

 Mangin, Sur la gommose de la vigne, and Sur la pretendue 'Gommose 



N 2 



