THE SCOPE OF BOTANY. 669 



could be removed, but slowly by the processes of chemical non- 

 vital oxidation. Even the parasites are not wholly evils, for some 

 of these man has already tamed and compelled to perform some 

 of the most important domestic operations the raising of bread 

 and the making of cheese and vinegar. Alcohol is one product 

 of the activity of yeasts, and to these we owe our wines and 

 beers. The precision in the manufacture and the uniform quality 

 of the product of bread, cheese, vinegar, and beer have come 

 only within recent decades when the microscopic organisms upon 

 which these processes depend have become known and regularly 

 raised like wheat and cattle. Recent investigations plainly sug- 

 gest that greater precision and more uniform success can be ob- 

 tained in the production of wines and in the curing of tobaccos. 

 Doubtless we have but begun to domesticate the plant parasites 

 which can be made useful to man, and more extended investiga- 

 tions will probably show that many processes in the domestic and 

 other arts which are now tardy and uncertain can be carried on 

 rapidly and accurately. 



The science of bacteriology has now become so specially de- 

 veloped along medical lines that in this aspect it can scarcely be 

 counted longer a part of botany ; but we should not forget that 

 the first knowledge of the bacteria came through botanists, and 

 that the methods now employed in studying and combating them 

 were first suggested by botanists, and every teacher of botany 

 should regard it both a duty and a privilege to spread among his 

 pupils and the public in general such a knowledge of the habits 

 and effects of these minute organisms that public sentiment will 

 demand not only personal but municipal cleanliness. An adequate 

 supply of water, free from contamination at its sources and in its 

 passage to our houses, contributes not only to the comfort, but 

 greatly also to the health, of any community. The installation of 

 a system of sewerage, for the safe disposal of the extremely dan- 

 gerous waste matters of houses and stables, will come as soon as 

 public sentiment is enlightened as to the probability of fatal dis- 

 ease resulting from the infection of drinking water, milk, and 

 other uncooked foods from such decaying matters. It is now 

 known that street dust contains millions of organisms which, 

 when they find lodgment in human bodies, made suitable by 

 weakness for their growth, cause the most malignant maladies. 

 Even the dust of our rooms contains numberless organisms of 

 these same sorts. So it behooves us as intelligent people to strive 

 to bring about such cleanliness of streets and houses that these 

 dangers will be reduced to a minimum. 



The bacterial and fungous diseases of other animals than man, 

 and the diseases of plants, are still being studied by botanists. 

 We have only begun to know the dangers which menace the 



