2 | THE AMERICAN MONTHLY [Jan 
branch of medicine, but also a subject of especial interest 
to the microscopist. Without the aid of the microscope, 
little, if anytbing would to-day be known of pathogenic 
organisms, in which case the study of infections diseases 
would be materially impeded, and that progress so essen- 
tial to medicine and surgery, hopelessly retarded. 
THE DocTRINE OF SPONTANEOUS GENERATION. 
‘‘Among the early Greeks we find that Anaximander (43d 
Olympiad, 610 B. C.) of Miletus held the theory that ani- 
mals were formed from moisture. Empedocles of Agri- 
gentum (450 B. C.) attributed to spontaneous generation 
all the living beings which he found peopling the earth. 
Aristotle (B. C. 384) is not so general in his view of 
the subject, but asserts that ‘‘sometimes animals are form- 
ed in putrefying soil, sometimes in plants, and sometimes 
in the fluids of other animals.” Three centuries later, in 
his disquisition upon the Pythagorean philosophy, we 
find Ovid defending the same doctrine, while in the Geor- 
gics Virgil gives directions for the production of bees. 
Not only was the doctrine of spontaneous generation of 
life, current among the ancients, but we find it persist- 
ing through the Middle Ages, and descending to our own 
generation to be an accidental but important factor in the 
development of a new branch of science. In 1542, in his 
treatise called De ,Subtilitate, we find Cardan asserting 
that water engenders fishes, and that many animalsspring 
from fermentation. Van Helmont gives special instruc- 
tions for the artificial production of mice, and Kircher in 
his Mundus Subterraneous (chapter ‘De Panspermia Re- 
rum’’) describes and actually figures certain animals 
which were produced under his own eyes by the trans- 
forming influence of water on fragments of stems from 
different plants. About 1686, Francesco Redi seems to’ 
have been the first to doubt that the maggots familiar in 
putrid meat arose de novo. ‘*Watching meatin its pas- 
sage from freshness to decay, prior to the appearance of 
