if ' ^^ 



ITJiriVERSITYf 



THE BACTERIOLOGICAL LABORATORY 47 



for milk, as the cream always rises to the surface 

 and is so left to the last/ 



In all the vessels previously mentioned the 

 nutrient fluid is sterilised by heat ; but in certain 

 cases it is necessary to sterilise the fluid without the 

 application of heat : this is performed by means of 

 the apparatus devised by M. Chamberland, of the 

 Pasteur Institute. The fluid is forced by a hand- 

 pump through porous porcelain ; and by this means 

 it is sterilised. 



In addition to the apparatus, etc., already men- 

 tioned in this chapter, a well - fitted laboratory 

 should contain: gas-burners with mica chimneys, 

 water-baths, hot-water filters, platinum needles, 

 wire cages for test-tubes, test-tube stands, glass 

 damp chambers, graduated cylinders, glass dishes 

 and capsules, thermometers, syringes, meat press, 

 ' glass benches,' desiccators, anatomical jars, iron 

 box for glass plates, mouse cages, beakers, glass rods, 

 glass and india-rubber tubing, chemical balance and 

 weights, as well as the various nutrient materials, 

 stains, hardening, imbedding, and mounting mate- 

 rials, and chemical reagents. The last are useful 

 for the extraction and analysis of ptomaines and 

 similar bodies. 



Although we have detailed the most important 

 pieces of apparatus for the bacteriological labora- 

 tory, there are others of importance, but as these 

 are only used for special purposes they will be 

 described later in the volume, i.e. in their proper 

 places. 



