1880.) Destruction of Obnoxious Insects by Fungoid Growths. 579 
duction, is an example of how rapidly and thoroughly spores may 
permeate any region when all the conditions are favorable to their 
growth. z ; 
_ In examining the question as proposed by Dr. Hagen, many 
facts must be taken into account before deciding upon the prob- 
able results. It must be remembered that the air is at all times 
charged with the spores of fungi. Dr. Cunningham found that 
“spores and other vegetable cells are constantly present in atmos- 
pheric dust, and usually occur in considerable numbers; the 
majority of them are living and capable of growth and develop- 
ment.” 
Dr. S. M. Babcock, who is determining the chemical changes 
of cheese during the curing process, finds it impossible to avoid 
mold in the curd except by heat and anesthetics (ether and 
chloroform). He states that the spores seem to be in the very 
milk used in the experiments. 
In the Botanical Laboratory, where molds and yeast are culti- 
vated at certain times for experimentation, the air soon becomes 
charged with spores. _ 
Growing in the same laboratory and rooms directly connected 
with it, are plants which require constant care lest they be over- 
run with their several insect. pests. No disease appears to have 
attacked these insects. It may be said that they do not feed upon 
the yeast, and for this reason escape. It is not necessary that the 
Spores be eaten by the insect in the case of the fly fungus (Am- 
Pusa musce). Huxley says? “It has been ascertained that 
when one of the spores falls on the body of a fly, it begins to 
germinate and sends out a process which bores its way through 
the fly's skin; this having reached the interior cavity of the body, 
Sives off the minute floating corpuscles which are the earliest 
Stages of Empusa. The disease is ‘contagious,’ because a healthy 
fly coming" in contact with a diseased one from whith the spore- 
bearing filaments protrude, is pretty sure to carry off a spore or 
two, It is ‘infectious,’ because the spores become scattered 
about all sorts of matter in the neighborhood of the slain flies.” 
In this connection it should be noted that while the insects 
which infest more or less the plants growing in the laboratory 
" Microscopical Examinations of Air,” from the “Ninth Annual Report of the 
Sanitary Commissioner.” Calcutta, 1872. 
ec : 
“ Lay Sermons, Addresses and Reviews,” p- 372. 
