VITALITY OF PUTKEFACTIVE OEGANISMS. 203 



But above all the practical question arises : — May not 

 the surgeon have to fight sometimes against enemies 

 like those here described? The particular germs with 

 which I have been so long contending act on both fish 

 and flesh in the manner described. How would they 

 behave in the wards of an hospital? Can they cause 

 wounds to putrefy? and if so, would they succumb to 

 the disinfectants usually applied? These are questions 

 the weighty import of which will be best understood by 

 the enlightened follower of the antiseptic system, and 

 -which he will know how to answer for himself. 



§ 20. Remarks on Acicl^ Neutral, and Alkaline 

 Infusions. 



In the foregoing section reference was made to the 

 comparative deportment of acid and neutral infusions. 

 There can be no doubt of the fact that, for the nutrition 

 and multiplication of Bacteria, acid infusions are less 

 suitable than neutral or slightly alkaline ones. In 

 acid infusions exposure to the common air sometimes 

 copiously developes Penicillium, while it fails to de- 

 velope Bacteria. It is also true that exposure for a 

 certain time to a certain temperature may in many 

 cases prevent the appearance of life in an acid infusion, 

 and fail to prevent it in a neutral or slightly alkaline 

 one. 



In the present inquiry this has been frequently 

 found to be the case. I have many closed chambers, 

 for example, to which the process of 'discontinuous 

 heating,' to be subsequently described, has been applied ; 

 and with them it has proved a common experience that 

 an amount of heating which has rendered acid infusions 

 of hay permanently barren has failed to sterilize the 

 corresponding neutral infusions. Moreover, in the 



