ZOOLOGY AND BOTANY, MICROSCOPY^ ETC. 99 



of the characters by which the various species of Saccharomyces may- 

 be distinguished from one another. In all the species examined the 

 ascospores were never developed below a minimum temperature of 

 from 0*5° to 3° C, or above a temperature of about 37 • 5° C. 



Hansen finds that some forms of Torula as well as of Saccharomyces 

 can invert and also cause alcoholic fermentation ; while others show 

 the latter phenomenon only. 



Alcoholic Ferments.* — L. Bontroux employs as diagnostics of 

 the species of fungus that induce fermentation the form of the 

 vegetative cells, whether elongated or oval, whether they occur singly 

 or in colonies, their fermenting activity, and their power of resisting 

 acids and high temperatures. He describes as many as nineteen 

 species of Saccharomyces, but some of them are forms of other fungi, 

 as Oidium lactis, Deraatium, &c. 



Magnin's ' Bacteria.'f — The second edition of this book contains 

 not only Cohn's accepted provisional classification of the Bacteria, 

 but a general resume of the latest labours in this difficult study, 

 largely supplemented by the experimental observations of Dr. G. M, 

 Sternberg, the translator. Scarcely any subject since the time of 

 Jenner has attracted so much attention as the question of the proof 

 of the infectiveness of certain of the bacteria. Opinions have 

 fluctuated not only in connection with the difficulty of proof required, 

 but also from the differences in the methods of experimenting. In 

 some cases pure cultures have not been made use of, and in others 

 the series of observations have not been of a sufficiently extended 

 nature to determine correctness in the results. Dr. Sternberg is very 

 critical in accepting some of the conclusions and statements made by 

 others ; and hence he has taken the precaution to lessen any objections 

 that may be made against his own observations, which are therefore 

 the more valuable and trustworthy. At the same time he avoids 

 accepting the evidence where the subject is still under serious dis- 

 cussion. When the experiments are of a positive nature, as in the 

 virulence of his own saliva when injected into rabbits, he does not 

 hesitate to join the ranks of those who insist upon the hacteria, 

 bacilli, or micrococci being the cause of the malady induced, and not 

 the sepsin or septic product produced by the microrganism, as has 

 been insisted upon by some. 



The fuller our knowledge of the role these invisible organisms 

 play, the greater the facility of establishing the laws of hygiene and 

 the means, if not of eradicating our common enemies, yet of lessening 

 the virulence. Whether we are to accept Zopf 's views of all forms 

 being originated by development from the same organism ; whether 

 the common forms by transmission through various living organisms, 

 or certain media, in themselves harmless or hurtful, obtain, increase, or 

 lose their virulence ; whether by the slow progress of evolution gathered 



* Bull. Soc. Linn. Normandie, iii. (1883) 42 pp. See Bot. Centralbl., xv. 

 (1883) p. 329. 



t Magnin, Dr. A., 'Bacteria. Translated witli additions by Dr. G. M. 

 Sternberg-, F.E.M.S.' 487 pp., 12 pis., and figs. 2nd ed., 8vo., New York, 1883. 



H 2 



