i6a PATHOGENIC BACTERIA.

The animal should be tacked to a board if small, or
tied, by cords fastened to the legs, to the corners of a
table if large, and should be dissected with sterile knives
and scissors. When a culture is to be made from the
interior of an organ—say the spleen—it should be incised
deeply with a sterile knife and the culture made from
its centre.

Fragments intended for subsequent microscopical ex-
amination should be cut very small (cubes of i c.cm.),
placed in absolute alcohol for a few hours, then trans-
ferred to weaker alcohol, 80-90 per cent, for preserva-
tion. The technique of imbedding and staining the tis-
sues can be found in almost any reliable text-book on
pathology or on the special subject of microscopical
technique.