1 8 BACTERIOLOGY 



sufficiently definite, to fit this and other related structures, for it 

 is a question whether every bacteriologist can always see a fir 

 tree turned upside down as he looks at a gelatin stab culture of 

 Bact. mycoides. Fliigge compares the growth in gelatin stab of 

 the bacillus of the mouse septicaemia " to the brush bristles 

 used for cleaning test tubes." Such methods of description 

 may be reaUstic and wonderfully exact, but it would be better to 

 have a term, as villous, to express this particular type of struc- 

 ture whenever it occurs. Such terms would also possess a 

 certain elasticity of meaning, more generally applicable to 

 different cultures of the same organism than comparisons to fir 

 trees and test tube brushes. Furthermore, the appearance, 

 especially under the microscope, of colonies and growths is sub- 

 ject to such minor variations, to say the least, that the very exact 

 and detailed descriptions which we often read possess no value 

 except as a perfect word picture of the particular colonies or 

 what not, which the writer may happen to have observed at 

 some particular time ; and while these exact descriptions are 

 useful in laboratory notes, with the view of eventually drawing 

 up a final average description, they are misleading to others, 

 who look for exact duplicates in their observations. A recent 

 description of the gelatin colonies of Bact. mycoides reads : "After 

 twenty-four hours the colonies appear as hazy, ill-defined spots, 

 with small, indistinct, sHghtly denser centres. On close in- 

 spection, they are seen to consist of a loose felt-work. The gela- 

 tin is liquefied in a short time. Under a low power, a network 

 is seen, formed of very long, hair-Hke filaments, which are some- 

 times straight and sometimes deHcately undulating, running in 

 all directions and crossing one another at all angles. Toward 

 the centre of the spot the network is somewhat denser, and 

 here a dark, Veil-defined nucleus may be found. If the colonies 

 are few in number, they may very soon attain a diameter of a 

 centimetre or more." This is a fair sample of the verbosity 

 often found in bacterial descriptions. The author had in mind 



