APPENDICES. 



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

 .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. 260. ISRAEL'S CASE. side, and each 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ment withdrawn with 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. 261. DAMP CHAMBER FOR POTATO- 

 CULTIVATION. 



