20 
The possibility of utilizing the fungus parasites of insects for 
the destruction of injurious species was greatly enhanced by the 
discovery of methods for the pure culture of fungus species on 
artificial substances. These methods with bacteria resulted from 
a prolonged controversy over the doctrine of spontaneous genera¬ 
tion which ran through several years about the middle of this 
century. General culture methods with higher parasitic fungi were de¬ 
vised between 1860 and 1870 by botanists— Tulasne, De Bary, and 
others—engaged in a study of the life histories and metamor¬ 
phoses of fungi. 
It will thus be seen that by 1870 everything had been made 
known which was necessary to a scientific foundation for economic 
experiments with at least four great classes of fungous and 
sporozoan diseases of insects; and a very pointed suggestion of 
their utilization for the destruction of injurious species was in 
fact contained in observations on the muscardine of silkworms 
published thirty years before. This idea had indeed been already 
several times definitely expressed, and some rather crude practical 
experiments had been undertaken by Bail in Germany, unfor¬ 
tunately based in large measure on mistaken ideas of the relation¬ 
ships of different fungus forms. 
THE SUBJECT IN AMERICA. 
The economic entomologists of America were all this time seem¬ 
ingly without knowledge of these European observations and 
investigations, being perhaps too strictly entomological to have 
access to the proper sources of information; and when Dr. Henry 
Shimer, of Carroll county, Illinois, published in the Proceedings 
of the Philadelphia Academy of Sciences for 1867 a detailed ac¬ 
count of his observations on the disappearance of a highly 
destructive outbreak of the chincli-bug in 1865 in consequence of 
the appearance and rapid propagation among them of what we 
now recognize as unquestionably a form of muscardine, neither 
he nor any other of our entomologists understood the occurrence. 
Shimer himself regarded the disease as an “epidemic, doubtless 
produced in a measure by deficient light, heat, and electricity, 
combined with excessive humidity of the atmosphere, whereby an 
imperfect physical organization was developed.” “The disease was 
at its maximum,” he says, “during the moist warm weather that fol¬ 
lowed the cold rains of June and the first part of July. The 
young chincli-bug spent a great portion of its time on or near the 
ground, where its body was colder than the atmosphere, hence, 
upon philosophical principles, there must have been an excessive 
precipitation of watery vapor in the bronchial tubes. These are 
the facts in the case, but in the midst of the great obscurity that 
envelops epidemic diseases among men it would be only idle spec¬ 
ulation to attempt to define the cause more definitely than the 
physiological laws already observed seem to indicate.” Concerning 
the fungous accompaniments of this disappearance he only says: 
“Plenty of dead bugs may be seen everywhere lying on the 
ground, covered with the common mold of decomposing animal 
