| 摘要 |
<p>Appts. incorporates a dosing-head connected by a crosspiece to the top of a shaft which can be moved axially. The bottom of the shaft is connected to disc which carries a pawl. The pawl can engage in teeth in a rotary plate on which the sample receptacle support is placed. The dosing-head incorporated a syringe fixed in the head by a screw or by springs and capable of vertical adjustment. The cross-piece carries a rod on which is a holder for a piece of cleaning cloth, surrounding the stem of the syringe. The toothed rotary plate and the disc carry stops and grooves. At each rotation of the cross-piece the pawl moves the plate to the exact position for the sample to be introduced. Appts. is useful for introducing very small volumes of samples into very small receivers e.g. holes in a relatively flexible and easily damaged substance such as agar-agar or agarose gel. Particular cases are analytical procedures, e.g. radial immunological diffusion of antigens in a gel vehicle contg. antibodies. In this process, a gel vehicle contg. antibodies e.g. agar-agar or agarose, is spread uniformly on the base of a circular receiver and cavities are formed in a radial arrangement to receive the soln. of the antigen. Device gives safer charging of plates of manual prepn. Cavities receive samples in same position each time because of predetermined transport.</p> |
