272 BACTERIOLOGY. 
closed space, where the opportunities for evaporation 
are slight. They should always be kept inclined. 
“‘The ordinary cotton-plugged test-tubes I do not 
use, because of the rapid drying out permitted by 
them as well as the opportunities for infection with 
fungi. Instead, a tube is used which has a ground- 
glass cap fitted over it. This cap contracts into a 
narrow tube plugged with glass-wool; this plug is not 
disturbed. The tube is cleaned, filled, and inoculated 
by removing the cap. With sufficient opportunity for 
the interchange of air very little evaporation takes place, 
and contamination of the culture is a very rare occur- 
rence. In inoculating these tubes bits of tissue which 
include tuberculous foci, especially the most recent, are 
torn from the organs and transferred to the serum. 
Very little crushing, if any, is desirable or necessary. 
I think many failures are due to the often futile 
attempts to break up firm tubercles. Nor should the 
bits of tissue be rubbed into the surface, as is some- 
times recommended. After a stay of several weeks in 
the thermostat I usually remove the tubes and stir 
about the bits of tissue. This frequently is the occa- 
sion for a prompt appearance of growth within a week, 
as it seems to put certain still microscopical colonies in 
or around the tissues into better condition for further 
development. The thermostat should be fairly constant, 
as urged by Koch in his classic monograph; but I look 
upon moisture as of more importance. If possible a 
thermostat should be used which is opened only occa- 
sionally. Into this a large dish of water is placed, 
which keeps the space saturated. Ventilation should 
be restricted toa minimum. As a consequence, moulds 
grow luxuriantly, and even the gummed labels must be 
