(c) _Toxins._--Prepared by previously described methods (_vide_ page 318), are manipulated in a similar manner to cultivations in fluid media. (d) _Pathological Products._--Fluid secretions, excretions, etc., such as serous exudation, pus, blood, etc., are treated as fluid cultivations; but if the material is very thick or viscous, a small quantity of sterile bouillon or normal saline solution may be used to dilute it, and thorough incorporation effected by the help of a sterile platinum rod. Solid tissues, such as spleen, lymph glands, etc., may be divided into small pieces by sterile instruments and rubbed up in a sterilised agate mortar (using an agate pestle), with a small quantity of sterile bouillon, and the syringe filled from the resulting emulsion. [Illustration: FIG. 175.--Holding rabbit for shaving.] If it is desired to inoculate tissue _en masse_, remove from the material a small cube of 1 or 2 mm. and introduce it into a wound made by sterile instruments in a suitable situation, and occlude the wound by means of Michel's steel clips and a sealed dressing. ~Method of Securing Animals During Inoculation.~-- For the majority of inoculations, especially when no anæsthetic is administered, it is customary to employ an assistant to hold the animal (see Fig. 175). If working single handed Voge's holder for guinea-pigs, is a useful piece of apparatus the method of using which is readily seen from the accompanying figures (Figs. 176, 177). The instrument itself consists of a hollow copper cylinder, one end of which is turned over a ring of stout copper wire, and from this open end a slot is cut extending about half way along one side of the cylinder. The opposite end is closed by a "pull-off" cap and is perforated around its edge by a row of ventilating holes, which correspond with holes cut in the rim of the cap. In the event of the animal resisting attempts to remove it from the holder backwards, this cap is taken off and the holder placed on the table and the guinea-pig allowed to walk out. [Illustration: FIG. 176.--Taking guinea-pig's temperature.] To provide for different-sized animals, two sizes of this holder will be found useful: 1. Length, 16 cm.; breadth, 6 cm.; size of slot, 8 cm. by 2.5 cm. 2. Length, 20 cm.; breadth, 8 cm.; size of slot, 10 cm. by 2.5 cm. A convenient holder for mice and even small rats is shown in figure 178, the tail being securely held by the spring clip. Needless to say, the holder should be entirely of metal, and the wire cage detachable and easily renewed. [Illustration: FIG. 177.--Voge's holder.] When the animal is anæsthetised, it is more convenient to secure it firmly to some simple form of operating table, such as Tatin's (Fig. 179), which will accommodate rabbits, guinea-pigs, and rats: or to the more elaborate table devised by the author (Fig. 180). [Illustration: FIG. 178.--Mouse holder.] [Illustration: FIG. 179.--Tatin's operation table.]