868 SUMMARY OF CURRENT RESEARCHES RELATING TO 



was at first 350 atmospheres, and at the end 500. From the 26th of 

 June the infusion swarmed with bacteria ; a further examination on the 

 4th and 11th of July gave the same result. The experiment was 

 stopped on the 24th of July, the day on which the putrefaction of 

 the vegetable tissues was complete in the control tube. This 

 tube contained nothing but liquid and a whitish pellicle. 



The tube kept under a pressure of 350 to 500 atmospheres for 

 fort y-two days, presented the same appearance, but a closer examina- 

 tion showed striking differences : — 



Infusion imder 23ressure. Infusion left in air. 



No smell, acid reaction, numerons Nauseous odour, alkaline reaction, 



microb es, active, generally small ; numerous microbes, some active, others 



rods, s hort and fine, with forms re- motionless ; rods generally larger than 



sembli ng those already described. in the other infusion ; long bacteridian 



filaments. 

 No special coloration by iodine. No special coloration by iodine. 



Fusiform cells (yeast or mould ?) In- 

 fusoria. Pleuronema chrysalis. 



Of two tubes heated for ten minutes in a water-bath, at boiling 

 point, one containing the liquid of the infusion under pressure, and an- 

 other with the liquid of the infusion left in the air, the former was 

 found sterile, while the latter gave abundant cultures on the following 

 day. It therefore appears that in the greater number of cases both 

 the chemical processes, and perhaps also the microscopic agents of 

 putrefaction differ according as it is produced in the open air or 

 under pressure. However this may be, the fact of the complete 

 destruction of the organic matter by microbes which live under high 

 pressures is, the author considers, formally established. 



It is much more difficult to know what is the degree of resistance 

 to high pressui'es presented by the higher microscopic organisms : 

 infusoria, unicellular algae, rotifers, &c. The privation of light and 

 the progressive diminution of oxygen are so many causes of death 

 added to the abnormal pressure. The author has, however, as already 

 stated,* taken living Infusoria and even Rotifers and Tardigrades 

 from the apparatus, after they have been subjected during 24, 48, 

 and 72 hours to pressures of from 300 to 500 atmospheres. But, on 

 the other hand, in tubes kept at a lower pressure for a much longer 

 time there was nothing living except the microbes. Was not this 

 result owing in great measure to the absence of oxygen ? 



To satisfy himself on this head he prepared two tubes with the 

 game infusion and put each under a pressure of 350 atmospheres, the 

 one with a reservoir of abundant air, the other without any air. At 

 the end of twenty-one days the aerated tube still contained a number 

 of Chlamydococcus pluvialis alive and active. They were all dead in 

 the other tube, and with the exception of the microbes, neither tube 

 contained any other living organisms. To appreciate these facts at 

 their full value it must not be forgotten that Chlamydococcus is re- 

 nascent, and that it encysts itself for protection from atmospheric 

 disturbances. 



* See this Journal, ante, p. 547 (let note). 



