~Kolle's Culture Flasks~ (Fig. 4).--These thin, flat flasks (to contain agar or gelatine, which is allowed to solidify in a layer on one side) are extremely useful on account of the large nutrient surface available for growth. A surface cultivation in one of these will yield as much growth as ten or twelve "oblique" tube cultures. The wide mouth, however, is a disadvantage, and for many purposes thin, flat culture bottles known as ~Roux's bottles~ (Fig. 5) are to be preferred. [Illustration: FIG. 4.--Kolle's culture flask.] [Illustration: FIG. 5.--Roux's culture bottle.] [Illustration: FIG. 6.--Guy's culture bottle.] [Illustration: FIG. 7.--Filter flask.] An even more convenient pattern is that used in the author's laboratory (Fig. 6), as owing to the greater depth of medium which it is possible to obtain in these flasks an exceedingly luxuriant growth is possible; the narrow neck reduces the chance of accidental contamination to a minimum and the general shape permits the flasks to be stacked one upon the other. ~Filter Flasks or Kitasato's Serum Flasks~ (Fig. 7).--Various sizes, from 250 to 2000 c.c. capacity. These must be of stout glass, to resist the pressure to which they are subjected, but at the same time must be thoroughly well annealed, in order to withstand the temperature necessary for sterilisation. All flasks should be either of Jena glass or the almost equally well-known Resistance or R glass, the extra initial expense being justified by the comparative immunity of the glass from breakage. ~Petri's Dishes or "Plates"~ (Fig. 8, a).--These have now completely replaced the rectangular sheets of glass introduced by Koch for the plate method of cultivation. Each "plate" consists of a pair of circular discs of glass with sharply upturned edges, thus forming shallow dishes, one of slightly greater diameter than the other, and so, when inverted, forming a cover or cap for the smaller. Plates having an outside diameter of 10 cm. and a height of 1.5 cm. are the most generally useful. A batch of eighteen such plates is sterilised and stored in a cylindrical copper box (30 cm. high by 12 cm. diameter) provided with a "pull-off" lid. Inside each box is a copper stirrup with a circular bottom, upon which the plates rest, and by means of which each can be raised in turn to the mouth of the box (Fig. 9) for removal. ~Capsules~ (Fig. 8, b and c).--These are Petri's dishes of smaller diameter but greater depth than those termed plates. Two sizes will be found especially useful--viz., 4 cm. diameter by 2 cm. high, capacity about 14 c.c.; and 5 cm. diameter by 2 cm. high, capacity about 25 c.c. These are stored in copper cylinders of similar construction to those used for plates, but measuring 20 by 6 cm. and 20 by 7 cm., respectively. [Illustration: FIG. 8.--Petri dish (a), and capsules (b, c).] [Illustration: FIG. 9.--Plate box with stirrup.] ~Graduated Pipettes.~--Several varieties of these are required, viz.: