106 THE POPULAR SCIENCE MONTHLY. 



gillus, a fungus allied to the microbes. Since then it has been' 

 enough to sow the tubs in which the fermentation proceeded with 

 the pure Aspergillus to obtain a better return and an opium of 

 superior quality in only one or two months. 



In the preparation of several most indispensable alimentary 

 products certain micro-organisms, domesticated as it were, prove 

 themselves incomparable chemists. Without them these prepara- 

 tions would be impossible. Among such products are bread, alco- 

 hol, wine, beer, and such fermented substances as koumiss, cheese, 

 and sauerkraut. 



These microbes are inferior alg&B formed of one cell, usually 

 with an envelope. They live almost everywhere on and with liv- 

 ing beings, in the ground, in water, on solids, etc., and multiply 

 with extreme rapidity. They produce a great variety of actions, 

 some of which, as we have seen, are beneficial, while others are 

 injurious. 



As microbes decompose dead matter, so they are capable of 

 disorganizing living matter. Some species have this power in a 

 marked degree, which is distinguished as virulence. They are 

 called pathogenic microbes, which means capable of causing ill- 

 ness. Each species of pathogenic microbe produces a particular 

 kind of disease, and has a power that varies considerably accord- 

 ing to a number of circumstances. The microbe alone, however, 

 can not produce disease : that requires the intervention of the 

 organism of the subject in which the disorder is to be developed. 

 The disease is, in fact, the resultant of the reaction of the one 

 upon the other of the two factors, the microbe and the organism. 

 According to the felicitous comparison of Prof. Bouchard, the 

 organism is a strong place, the microbe is its assailant, and the 

 struggle between them is the infectious disease. The condition of 

 the organic estate which the microbe endeavors to seize is there- 

 fore important. If the person is in general good health, he will 

 offer a vigorous resistance to the microbes. If, on the other hand, 

 his health is not perfect, there will be a point where the defenses 

 are weak, and his danger will be proportionately great ; for, as 

 M. Bouchard said some time ago, one does not become ill till he 

 is already not in good health. There are many ways of getting 

 into poor health. It may be done by a number of processes, 

 which may be summarized under the two categories of troubles 

 of the organic functions or lesions of the tissues. Some of these 

 pathogenic processes depend directly on a variety of social in- 

 fluences. 



Wealth and poverty are alike efficient factors of disease. The 

 rich man, by his often superabundant diet, his neglect of exercise, 

 and his excess of luxury, readily contracts obesity, gout, or dia- 

 betes ; his kidneys and his heart are frequently afflicted with dis- 



