ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 361 



asbestos into a sterilized flask, the pinch.-cock opened, and the broth 

 allowed to enter the flask, the canula withdrawn, and other flasks 

 filled. A sterilized cotton plug is placed above the asbestos one in 

 the flasks, and they are set in the stove at 35° C. for proving. No 

 failures are recorded with this plan. These standard flasks hold 

 about 1/4 litre, and are useful for estimating the number of germs in 

 water by the plan that will be presently described ; otherwise small 

 experimental flasks of 10 cc. are filled directly from the digester. 

 The necks of these small flasks are long and narrow, and for neces- 

 sary precaution the top of the tube-neck is covered with sterilized 

 asbestos, and over it is placed a tube-cap with a plug of cotton in it, 

 the lower edge being rounded off by the flame ; this is fitted over the 

 little flask-neck, the space between the neck and cap being closed by 

 the overlying asbestos, some being carried down the sides when the 

 cap is fitted on. Through this top layer of asbestos, after the removal 

 of the cap, the pointed canula can be easily passed without displacing 

 the layer over the top of the neck-tube. When charged they are 

 placed in the stove at 160° C, not more, for some time. This plan 

 has answered well, but control experiments are always made at the 

 same time. 



To collect the water for analysis and to estimate the number of 

 germs in a given volume. Dr. Fol takes a tube and places two plugs 

 of asbestos at one end, a little distance apart ; the other end is then 

 drawn out, sealed, heated, and the tube bent twice at a right angle, 

 bayonet fashion, the bends being some little distance from each other, 

 like the metal part of a carpenter's drill-stock. To collect the water 

 the plugged end is attached to a caoutchouc tube for aspiration, and 

 the point after due flaming is broken off by sterilized pliers, either 

 before entering or whilst beneath the water, so as not to vitiate the 

 result by the use of another vessel. For taking deep water from the 

 lake, the tubes are sealed at both ends, then heated, and fixed to a 

 metal stem or support also flamed, having a movable branch or arm 

 that can be actuated at some distance by a connected pull-wire, so as 

 to cause rupture of the point, by which the water enters so as to 

 partially fill the tube, then by turning the point upwards a bubble of 

 the sterilized air inside is made to occupy the point, and this is at 

 once sealed. This bayonet curved tube admits of manipulation 

 without wetting the asbestos plugs, which must be avoided. For 

 analysis the water is agitated in the tube, the point cut off, a few 

 drops allowed to escape, and the estimation made of the number of 

 germs after the method in use by Dr. Mi quel, i. e. by dilution with 

 sterilized water, to be afterwards distributed in prepared culture 

 flasks, but instead of water it is mixed directly with the sterilized 

 broth, and this is distributed into sterilized empty flasks. 



For this a burette narrowed at each end is used of 100 cc, 

 divided into tenths of a centimetre, and numbered so that 100 cc. 

 corresponds exactly with the inferior orifice and is at a little dis- 

 tance from the upper end. The burettes are sterilized in a special 

 stove, the orifices closed by asbestos and attached caoutchouc tubes, 

 which are previously washed with oxygenated water. For use, the 



