KNOWLEDGE • 



[JoNE 16, 1882. 



out from them, and finally separate. Under favourable 

 conditions, Uiis process goes on so Lxst that scores of the 

 little plants soon become thousands, and the thousands 

 millions and billions by this simple method of rapid 

 budding. Many of the higher plants, besides propagating 

 by seeds, which result from the cooperation of male and 

 female organs, also multiply by buds. Some of the begonias 

 exemplify this in a striking way, and there is a lily, common 

 in gardens (bulhi/ennii), which produces black bulbils all 

 up iu st<:-m. The yeast plants are not, therefore, excep- 

 tional in the budding process, and their mode of nutrition 

 is found to be the same in principle as that of the higher 

 vegetation. The yeast plants are capal)le of taking oxygen from 

 the air, if in contact with it, or, as tish do, from air dissolved 

 in w.iter ; but when they cannot get enough this way, they 

 supply themselves by decomposing the sugar in the solutions 

 of malt or other saccharine materials they are employed to 

 ferment. M. Pasteur says : " Fermentation by yeast, the 

 type of all ferments properly so-called, presents to us the 

 direct consequenco of the work of nutrition, assimilation — 

 in one word, of life — effectuated without free oxygen. The 

 heat consumed in this work must necessarily be obtained 

 in the decomposition of the fermentable matter, that is to 

 say of the sugar, which, after the manner of explosive sub- 

 stances, disengages heat in its decomposition. Fermenta- 

 tion by yeast appears thus essentially allied with the power 

 of this small cellular plant to perform a kind of breathing 

 ■with the oxygen combined in sugar." Other plant-cells 

 induced to live under similar conditions arc found to be 

 provocative of fermentation. 



In alcoholic fermentations of eitlicr wine or beer, 

 there are other matters present besides the saccharine 

 ones. Some of these belong to the albuminous class, and 

 besides carbon, hydrogen, nitrogen, and oxygen, they 

 contain sulphur and phosphorus, and these, though in 

 small proportions, contribute to the mobility and insta- 

 bility of the wine-must or sweet-wort of the beer. The 

 fermentiible fluids also contain some mineral matters 

 which the great plants re<|uire, as do the higher kinds of 

 vegetation, for their perfect growth. 



The respiratory acts of plants consume oxygen and lead 

 to the evolution of carbonic acid. Their nutritive acts 

 include the digestion of carbonic acid and the evolution of 

 oxygen, which produces a slow combustion, and when this 

 proc<»-S3 is carried on l)y the microferments, fungi, <tc., it 

 may completely destroy organic substances, as in cases of 

 putrefaction and decay. If yeast alone operates in wine 

 or bcicr fermentation, the chief result is the resolution of 

 the sugar into alcoholic and carbonic acid, with small 

 quantities of succinic acid and glycerine. 



Schutzcnberger states that 95 9 parts of cane sugar con- 

 tain Hi carbon, Gl hydrogen, and 491 oxygen; and 

 give OrG of alcohol, containing 2fi9 carbon, C-7 hydrogen, 

 and 180 oxygen -f- 13 5 carbon and oxygen combined into 

 carbonic acid, or, as chemists would call it, carbon dioxide. 

 Dumas e8timat<;d that to decompo.se one gramme (Ifj-i 

 grains) of sugar in one hour, about 400 milliards 

 (400,000,000,000) yeast cells must be at work. 



The yeast plant might have been dfwcribcd without so 

 much reference to chemistry, but the general nature of 

 fermentations cannot be understood without such explana- 

 tions; and if the student beginning these inquiries will 

 take the trouble to understand what a commotion the 

 growth of yeast makeji in saccharine solutions, the work 

 done by other ferments will lie more inteHigiblc. In our 

 next paper some of those which are often associated with 

 yeast, to the detriment of beer and wine, will be described. 

 This action tlirows light upon the production of diseases by 

 special organisms. 



CONDUCT AND DUTY.* 



IN all ages of which any record has reached us, men of 

 advanced mind (in their own age) have analysed the 

 principles which regulate conduct, and have discussed those 

 which should do so. In our own time the analysis of 

 ethical considerations has been more fully developed than 

 in any preceding age, — partly, perhaps, because a wider 

 experience is open to us, but chiefly because the progress 

 of the doctrine of evolution has thrown new light on the 

 subject No one who has thoughtfully studied the doctrine 

 of biological evolution can fail to see how important is 

 its bearing on the principles which determine duty and 

 .should rule conduct If the investigation of the laws of 

 evolution in their merely scientific aspect has not shown 

 this, the study of sociological works, such as those of 

 Herbert Spencer, must have forced even those who do not 

 accept the general doctrine of evolution, to perceive that 

 among those who do, the doctrine cannot but have a most 

 important ethical inlluence. For this reason, then, chiefly, 

 the subject of the book before us largely occupies men's 

 thoughts in our time. 



Mr. Leslie Stephen has long been known as among the 

 foremost and ablest of those who have dealt with the 

 science of ethics during the last quarter of a century. His 

 views on points of detail have been presented in essays 

 which have appeared from time to time in the Fortnightly 

 Jievieii^ and elsewhere. In the present volume, ho has not 

 collected such essays together, but has dealt with the 

 general suVyect dc novo : and he has here " attempted to 

 lay down an ethical doctrine in harmony with the doctrine 

 of evolution, so widely accepted by modern men of science." 

 He remarks well that " problems of this kind require to be 

 discussed in every generation with a change of dialect, if 

 not with a corresponding change of the first principles." 

 The standpoint from which he views the general subject 

 differs from Mr. Spencer's. The great teacher of the modern 

 doctrines of sociology has worked out an cncyclopajdic 

 system, of which his principles of ethics are the outcome. 

 Mr. Stephen, starting from the old ethical theories, has 

 endeavoured to bring them into harmony with scientific 

 principles, which he takes for granted. It is well that the 

 suliject should be examined from both points of view, that 

 it may be seen how far the results coincide, — as, of course, 

 they should do, if the general principle underlying both 

 lines of argument is sound. 



We recommend this work to all who have examined the 

 subject from Mr. Spencer's point of view, to all who prefer 

 to examine it from Mr. Stephen's, and to all who, eschew- 

 ing the modern doctrines of evolution, and decrying the 

 supposed moral consequences of those doctrines, may wish 

 to know what, according to scientific reasoning, these con- 

 sequences are. These last, in particular, will be into 

 rested, we take it, to see how the moral laws which they 

 have been in the habit of regarding as imparted from 

 without, are regarded by science as springing from within 

 the body social. 



It would be impossible to describe in dc^tail the various 

 sections of this interesting work. Each chapter might 

 well form the subject of a complete essay, or of a volume 

 of discussion. The criterion which Mr. Stephen esta- 

 blishes in the progress of his work as the general prin- 

 ciple of conduct is simply this, that a man is virtuous or 

 the reverse, a worthy or an unworthy member of the com- 

 munity, in so far as he does or docs not conform to the 

 type defined by the healthy condition of the social organism 

 of which he forms part. This must not be confounded 



• The Hcience of Ethica, Viy Lkslie Stui'iien'. (Messrs. Smith, 

 Elder, & Co., I^ndon.) 



