28 
» f 
Its hidden presence among bugs which, as observed in the 
held, seem to be wholly free from it, may often be demonstrated 
by shutting up such bugs for two or three days in a moist atmosphere; 
but, on the other hand, as this procedure often fails to develop it, 
it is not always and everywhere present. 
4. Its characteristic fungus may be easily cultivated on certain 
mixtures of animal and vegetable substances, or on either of these 
substances alone—plain beef broth or simple agar-agar, for exam¬ 
ple. The cheapest and most satisfactory mixture thus far used 
is corn meal saturated with beef broth. 
5. It can only be grown on these media in the absence of the 
germs of fermentation and decay. If these are not excluded, they 
take possession of the surface, and the muscardine fungus will 
not grow in competition with them; methods of sterile culture are 
therefore indispensable. The most convenient apparatus of sterile 
culture used by us is a circular copper pan (PI. VIII) nine inches 
across and one inch deep, with straight sides, and a cover which 
shuts over the pan like the lid of a pill box. A less convenient 
but slightly safer apparatus is a Mason fruit-jar, with the metal 
cap altered by the insertion of a tube which may be plugged 
with cotton as a protection against bacteria and other fungus 
germs. (PI. V., Fig. 1). 
6. Propagation of this fungus to living insects is easy if the 
atmosphere is kept moist. We have found as yet little, if any, 
reason to believe that the cultivated Sporotriclium is any less 
active as an agent of infection than that grown on the insect 
body. Its spores will germinate on the surface of infected insects, 
sending their thread-like outgrowths through the cuticle; but 
soft-bodied forms, like caterpillars, are, as a rule, more easily 
infected than those with a hard crust. 
7. The distribution of the Sporotrichum in the field will have 
no immediate effect if the weather is dry, but spores may live in 
a dry state for many mouths, and may thus give origin to an 
outbreak of muscardine, if the weather changes, long after they 
have been distributed. 
_ 8. The readiest and most convenient method of rapid propaga¬ 
tion and general distribution of muscardine is to grow the fungus 
on corn-meal batter mixed with beef broth, by the sterilization 
methods of the bacteriological laboratory, and to distribute this 
cultivated fungus to farmers with instructions for its use. For 
its dissemination in their fields chinch-bugs are to be infected by ex¬ 
posure to the fungus in tight wooden boxes with a layer of earth in 
the bottom of each box. The imprisoned bugs must be supplied with 
food, which should be renewed as necessary, and the contents of the 
boxes must be kept continuously moist. As the bugs show evidence 
of disease, a part of them are to be scattered in the fields at inter¬ 
vals, their places being taken by fresh bugs put in the box. 
This operation is to be continued until the desired result appears. 
A more convenient method and one less liable to miscarriage 
through failure of the farmer to carry on successfully operations 
for the propagation of the fungus, is the distribution of the cul- 
