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APPENDICES. 



cementing a little piece of plate-glass at either end of a 

 slip (Fig. 259). 



Glass Rods. One dozen or more glass rods, twelve to eighteen 

 inches in length. They are employed for smoothly spreading out 

 the liquefied nutrient gelatine or agar-agar on the glass plates, etc. 



Thermometers. Two or three centigrade thermometers. 



(I) APPARATUS FOR PREPARATION OF POTATO-CULTIVATIONS. 



Israel's Case. Sterilising instruments in the flame of a Bunsen 

 .burner is most destructive. It is better, therefore, to have a sheet- 

 iron case (Fig. 260) to 

 contain potato-knives, 

 scalpels and other in- 

 struments, and to ster- 

 ilise them by placing 

 the case in the hot-air 

 steriliser for an hour 

 at 150 C. The box 

 can be opened at the 



FIG. 2GO. -ISRAEL'S CASE. side > and eacn instru- 



ment withdrawn with 

 a pair of sterilised forceps when required for ase 



Glass Dishes. Several shallow glass dishes are required for 

 preparing damp chambers for potato-cultivations (Fig. 261). The 

 upper, being the larger, fits 

 over the lower, and having 

 no handle, admits of these 

 damp chambers being placed, 

 if necessary, in the incubator 

 in tiers. The large size may 

 also be used in the same 

 way for plate-cultivations. 



Potato Knives. A 

 common broad smooth-bladed knife set in a wooden handle is sold 

 for this purpose. 



Scalpels. Half a dozen scalpels, preferably with metal handles, 

 may be kept especially for inoculating sterilised potatoes. 



Brush. A common stout nail-brush, or small scrubbing-brush, 

 is essential for cleansing potatoes. 



FIG. 2G1. DAMP CHAMBER FOR POTATO- 

 CULTIVATION. 



