184 
PROFESSOR TYNDALL ON THE DEPORTMENT AND VITAL 
Pig. 10. 
heating. In the absence of the liquid the fine tube reddens, fuses, and is hermetically 
sealed. The aspect of the bulb after it has been thus charged is shown at C, fig. 10. 
By this method, on the 20th of February sixteen bulbs were charged with infusions 
of old Heathfield hay and of a hard wiry hay from Guildford, not old. They were 
divided into four groups, four bulbs in a group. Each group embraced two acid and 
two neutral infusions. They were boiled for the following times : — 
1st group 10 minutes. 
2nd „ 20 
3rd „ 30 
4th „ 60 „ 
After the bulbs had sufficiently cooled, their sealed ends were removed by a file. 
On the 21st of February, less than twenty-four hours after their preparation, all 
these bulbs showed signs of yielding. On the 22nd they were all turbid, while, as 
regards the comparison of acid and neutral infusions, their condition was this : — 
f Guildford neutral distinctly more turbid than Guildford 
| acid. Scum on former, none on latter. 
1st group. 10 minutes. ^ Old Heathfield neutral not to be distinguished from 
old Heathfield acid. Both turbid and covered with 
scum. Much lightened in colour. 
I' Guildford neutral distinctly more turbid than the acid 
2nd group. 20 minutes. K liquid. 
I Old Heathfield neutral more turbid than the acid infusion. 
