INFECTION" EXPERIMENTS IX LABORATORY. 
25 
The bottles were opened July 23 and the number of Sporotrichum- 
covered bugs ascertained. 
CHECK BOTTLES. 
Bottle No 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 

1 






1 
1 
1 
Bottle No 
12 
13 
14 
15 
16 
17 
18 
19 
20 
Total. 

1 

1 
n 


1 
2 
9 
INOCULATED BOTTLES. 
Bottle No 
1 
2 3 
4 
5 
6 
7 8 
9 
10 
11 
Number of diseased bugs 
6 
5 
6 
7 
3 
3 
8 4 
2 
1 
9 
Bottle No 
12 
13 
14 
15 
16 
17 
18 
19 
20 
Total. 
Number of diseased bugs 
1 
1 
1 

1 
2 

4 
6 
63 
The five experiments pointed uniformly to one conclusion — that no 
mistake had been made in adopting artificially grown fungus in pref- 
erence to that found on dead bugs, especially when it was found that 
so much more could, with certainty, be procured. In a great major- 
ity of instances in which field inoculation was undertaken the natural 
presence of the diseased bugs in large amounts would have rendered 
ineffectual the scattering of the comparatively few bugs obtained 
from infection boxes. 
Dr. M. A. Barber, director of the clinical laboratories of the uni- 
versity and inventor of the technique by which single bacterial cells 
or spores may be manipulated at will, conducted some inoculation 
experiments that shed light on the problem of virulence and infec- 
tiousness of artificial cultures. He has outlined his work below : 
In the following experiments spores of Sporotrichum globuliferum 
were inoculated directly into the bodies of chinch bugs by means of 
very fine pointed pipettes made of hard Jena glass. Very small 
quantities of an emulsion of spores in salt solution were drawn into 
the tip of the pipette by means of a suction on a rubber tube attached 
to the blunt end of the pipette. The point of the pipette was then 
inserted into the leg or abdomen of the insect and the spores forced 
in by gently blowing into the rubber tube. Inoculation was done 
under a large simple lens. The same technique has been successfully 
used in the inoculation of flies, cockroaches, and other insects with 
bacteria and various microorganisms. 
The experiments with chinch bugs were undertaken largely for the 
purpose of testing the technique, and the number of series undertaken 
