VITALITY OF PUTEEF ACTIVE OEGANISMS. 197 



Each group embraced two acids and two neutral in- 

 fusions. They were boiled for the following times : — 



1st group 

 2nd „ 

 3rd „ 

 4th „ 



10 minutes. 

 20 „ 

 30 „ 

 60 



After the bulbs had sufficiently cooled, their sealed 

 ends were removed by a file. 



On the 21st of February, less than 24 hours after 

 their preparation, all these bulbs showed signs of yield- 

 ing. On the 22nd they were all turbid, while as 

 regards the comparison of acid and neutral infusions, 

 their condition was this : — 



' Guildford neutral distinctly more turbid 

 than Guildford acid. Scum on for- 

 mer, none on latter. 



Old Heathfield neutral not to be dis- 

 tinguished from old Heathfield acid. 

 Both turbid and covered with scum. 

 Much lightened in colour. 

 ^ Guildford neutral distinctly more turbid 

 than the acid liquid. 



Old Heathfield neutral more turbid than 

 the acid infusion. 

 [ Guildford neutral a little more turbid 

 than Guildford acid : difference small. 



Old Heathfield neutral more turbid than 

 the acid infusion ; the former with 

 scum, the latter none. 



Guildford neutral distinctly more turbid 

 than Guildford acid ; the former with 

 scum, the latter free from scum. 



Old Heathfield neutral somewhat more 

 turbid and scummy than the acid 

 liquid : difference not great. 



Here I take it to be absolutely certain that the 

 germs which resisted sterilization were contained in the 



1st group. 10 minutes. < 



2nd group. 20 minutes. 



3rd group. 30 minutes. - 



4th group. 60 minutes. 



