S 4 THE BACTERIA UNDER PHYSICAL AGENCIES. 



nutrient gelatin arranged themselves in the form of a feather, and 

 in such a manner that the individual rays grew in a slanting 

 upward direction. When the tubes containing the cultures were 

 placed radially on a rapidly-revolving horizontal glass disc, the 

 vegetation then developing assumed an appearance corresponding 

 to that already described, the individual rays, which extended 

 from the axis of the puncture, formed acute angles therewith, 

 the apertures of which M r ere reflected towards the centre of 

 the disc. This species therefore exhibits negative geotropism. 

 BEYERINCK (III.) erroneously, as the author conceives has 

 denied this fact. 



The lower fungi generally, and bacteria in particular, remain, 

 within wide limits, unaffected by high gaseous pressure. Thus, 

 SCHAFFER and FREUDENREICH (I.) and others have inoculated 

 samples of milk with different bacteria (those of anthrax and 

 typhus among them), and then exposed them for seven days to 

 -carbon dioxide at a pressure of fifty atmospheres, without being 

 -able to cause any appreciable injury to the organisms. Similar 

 "behaviour was also observed with oxygen under a pressure of 

 twenty-one atmospheres, prolonged for a week. There is, therefore, 

 no reason for hoping that liquids which are injuriously affected by 

 lieat can be sterilised in the cold by the aid of gas (C0 2 , O, air) 

 under high pressure. Eor exhaustive experiments on the influence 

 of high gaseous pressure on living creatures generally, and the 

 pathogenic ScMzomycetes in particular, we are indebted to Paul 

 Bert. 



