Ho 



POPULAR SCIENCE MONTHLY. 



will need all the powers of careful observa- 

 tion and industrious recording of which a 

 scientific man is capable. But while I em- 

 phatically regard these and similar problems 

 as worthy the attention of botanists, and 

 recognize frankly their commercial impor- 

 tance, I want carefully and distinctly to 

 warn all my hearers against supposing that 

 their solution should be attempted simply 

 because they have a commercial value. It 

 is because they are so full of promise as sci- 

 entific problems that I think it no valid argu- 

 ment against their importance to theoretical 

 science that they have been suggested in 

 practice. In all these matters it seems to 

 me we should recognize that practical men 

 are doing us a service in setting questions, 

 because they set them definitely. In the at- 

 tempt to solve these problems we may be 

 sure science will gain, and if commerce 

 gains also, so much the better for commerce 

 and indefinitely for us. But that is not the 

 same thing as directly interesting ourselves 

 in the commercial value of the answer. This 

 is not our function, and our advice and re- 

 searches are more valuable to commerce the 

 less we are concerned with it." 



Some New Facts regarding Teast. Some 

 interesting experiments have been under 

 way during the past few years regarding the 

 phenomena of fermentation. It has been 

 generally thought that the alcoholic fermen- 

 tation of sugar by yeast differs from the 

 ordinary hydrolytic processes of the enzymes 

 in that the actual presence of the living yeast 

 cell was an essential. Some investigators 

 have doubted this, however, and have thought 

 that alcoholic fermentation was simply an ex- 

 ample of ordinary enzyme action of special 

 complexity. These views were partially sup- 

 ported by some experiments of Dr. E. Buch- 

 ner, announced in the early spring ; and it is 

 now reported that later experiments from the 

 same laboratory still further confirm this 

 view, and, in fact, make it almost a certainty. 

 Dr. Buchner, by pounding up pure yeast with 

 quartz sand and adding a certain amount of 

 water, was able to squeeze out under a pres- 

 sure of from four hundred to five hundred at- 

 mospheres a liquid which, after thorough fil- 

 tering, was of an opalescent appearance and 

 possessed an agreeable yeastlike odor. All 

 care was taken to exclude any organism from 



the liquid, and it was found that under these 

 conditions it was able to excite alcoholic fer- 

 mentation in solutions of suitable sugars. 

 The addition of chloroform, even up to the 

 saturation point, does not inhibit the fer- 

 mentative process, and this, in conjunction 

 with the fact that the activity of the solu- 

 tion is not affected by the presence of the 

 ordinary antiseptie substances, and that the 

 solid residue, after evaporation at low tem- 

 peratures, is found to yield an active solution 

 even after being kept for two or three weeks, 

 seems to show conclusively that the fermen- 

 tation in these cases is not brought about by 

 living protoplasm in any form, but is really 

 due to an enzyme ferment which the author 

 calls zymase. This is further confirmed by 

 the fact that dried yeast heated to 100 for 

 six hours, while incapable of further devel- 

 opment, still yields an active solution when 

 treated with a sterilized thirty-seven-per-cent 

 sugar solution. 



Thirteen Tears' Progress in Physiology. 



The presidential address of Prof. Michael 

 Foster in the Physiological Section of the 

 British Association was devoted to a review 

 of the progress of physiology during the thir- 

 teen years since the association previously 

 met in Canada, and dealt largely in techni- 

 calities. The progress consists partly of the 

 continuation of investigations previously be- 

 gun, and of advance in investigations newly 

 entered upon. An example of the former 

 kind is the study of the mechanics of the 

 circulation. The researches of Hiirthle and 

 Tigerstedt, of Roy and Adami, and others 

 have left us wiser on this subject than be- 

 fore. So real, if not exciting, progress has 

 been made with the problems of muscular 

 contraction ; we are some steps measurably 

 nearer an understanding of what is the nature 

 of the fundamental changes that bring about 

 contraction, and what are the relations in 

 the changes in the structure of muscular 

 fiber. In respect to the beat of the heart, 

 we have continued to approach nearer to the 

 full light. Among other problems concern- 

 ing which knowledge has advanced are those 

 of the nature of secretion and of transuda* 

 tion, concerning which controversies have 

 raged that have not been wholly unprofit. 

 able. Included in the new subjects of re- 

 search are physiological chemi&try in gen- 



