1876 



Journal of Applied Microscopy 



A Simple Device for Storing Fluid Culture Media. 



In a laboratory in which certain fluid media are only occasionally used and 

 in small quantities at the time, it becomes necessary to keep the medium in bulk. 

 Then, every time the flask is opened and the cotton plug and neck of the flask 

 flared, the neck either cracks or breaks, or the medium becomes contaminated 

 if the neck is not flared sufficiently. Again, in a flask with only a cotton plug, 

 the medium evaporates. To obviate these difticulties the writer contrived a 

 simple device after considerable experimentation with several devices which had 

 to be abandoned as impractical or inefficient. The device is readily understood 

 from the accompanying drawing (Fig. 1). It consists of a flask, A, plugged with 



cotton and sealed with a mixture of equal 

 parts of paraffine and vaseline ; a bent 

 tube d and a syphon tube a h c. The flask 

 containing the medium is plugged. The 

 tube a b c passes through the plug, while 

 the tube d reaches the upper layer of the 

 plug, being only slightly embedded in it. 

 The end of the tube d is loosely filled with 

 cotton. The whole is sterilized, the plug 

 pushed down the neck, leaving about one- 

 half an inch space from the brim, which 

 is dusted freely with powdered sulphate of 

 copper and filled in to the point of overflow- 

 ing with a mixture of sterile paraffine and 

 vaseline. The object of adding vaseline to 

 the paraffine is to render the latter softer 

 and less retractive. This forms an air- 

 tight stopper. The syphon is started by 

 blowing through the tube d. Once started, 

 the flask is inclined in the direction opposite 

 the outlet, when the fluid will run back into the tube b. The level of the fluid in 

 b will be the same as in the flask A. The end of c is then sealed as well as the 

 end of d. The sealing of the tube d, however, is unnecessary if the flask does 

 not have to remain absolutely air-tight. To pour out the medium, the end of r, 

 after careful flaming, is broken oft" at one end of the narrowed points, and the 

 flask inclined in the direction of c. The rapidity of the flow can be made to 

 vary from a drop to a stream, depending on the inclination of the flask. On 

 this account, the idea suggested itself that this device could be utilized for 

 dropping bottles. The regularity and certainty with which the fluid can be 

 made to flow in drops render it equal if not superior to any dropping bottle on 

 the market, while the cost is far less. Another utilization of this arrangement 

 could be in the bacteriological examination of water when fractions of a c. c. 

 must be used. The water may be poured directly into one of these sterile flasks, 

 and the number of drops (at a certain rapidity of flow) per c. c. determined. It 



Fig. 1. — Device for Storing Fluid Media. 



