556 THE POPULAB SCIENCE MONTHLY, 



soda, to which '^L Dumas invited the attention of physiologists a year 

 ago ; the acetate of potassa, and others. Hitherto the physiological 

 virtues of active principles have been studied only with respect to the 

 higher order of animals: M. Dumas pointed out the great interest 

 there would be in examining the influence they exert over the lower 

 organisms charged with the elaboration of ferments, and over ferments 

 themselves. Such researches not only contribute to a better knowl- 

 edge of the mechanism itself according to w^hich these principles affect 

 the system of vital phenomena, but they also gain the most useful indi- 

 cations for the healing art. Indeed, beginning with the moment at 

 which M. Dumas and other chemists made known the result of their 

 examinations on this subject, coincident also in time with the experi- 

 ments of M. Davaine on septicaemia, a vast number of attempts were 

 entered upon, in hospitals and in laboratories, to discover to what ex- 

 tent these anti-fermenting substances hinder morbid fermentations. 

 These attempts are still proceeding ; we cannot foretell their success, 

 but we are authorized even now to say that they will not be barren of 

 advantage to the healing art. In this, as in all other departments of 

 scientific activity, we see abstract studies result in useful discoveries. 



As a general statement of the subject, all this immense work of 

 fermentations, putrefactions, and corruptions of organic matter, is effect- 

 ed in the world by a small number of species of microscopic cells and 

 filaments, by fungi and spores of the lowest order, of which the germs 

 fill our atmosphere. This is one of the most certain acquisitions of 

 modern science, one of the most important from the point of view of 

 natural philosophy, one of the most productive for those arts that are 

 concerned in improving the condition of mankind. We may now re- 

 gard it as firmly established ; but let us not forget that its establish- 

 ment has cost two centuries of investigations and labors. Leuwenhoek, 

 in the middle of the seventeenth century, was the first to reveal the 

 microscopic world of the air, and to conjecture its momentous func- 

 tions. What severe toil, what struggles and tedious trials, since the 

 observations of the Dutch micrograph, to the time of the experimental 

 studies of our contemporary and compatriot, M. Pasteur ! 



BIKDS-OF-PAEADISE. 



Bt JAMES H. PAETRIDGE. 



T 





HE Birds-of-Paradise are a small, but renowned family. They 

 received their name from the idea, entertained at one time, that 

 they inhabited the region of the Mosaic paradise. They live in a 

 small locality in Australasia, including Papua or New Guinea, and a 

 few adjacent islands. They are not easily tamed and kept confined ; 

 and few have been brought alive from their native locality. Mr. Beale 



