154 
PROFESSOR TYNDALL ON THE DEPORTMENT AND VITAL 
the turbidity of the straight-necked bulbs had increased, while a fatty scum had 
formed on the surface of -each. The two others were at the 
same time slightly but distinctly turbid. 
My inference from this experiment was that in neither the 
straight-necked nor the bent-necked bulbs had the germs been 
killed by the boiling, but that they were more damaged in the 
former than in the latter. 
It is here to be noted that a quantity of air, with its associated 
floating matter, was imprisoned above the infusion in every 
straight-necked bulb ; that in the case of the two bent-necked 
bulbs this air had been in part displaced by steam, the air 
which entered on cooling being sifted by the cotton-wool plugs. 
To this difference of treatment is to be attributed the observed 
difference of deportment. Unlike the thick cloudiness of their 
neighbours, the turbidity of the bent-necked bulbs, though 
distinct, was barely sensible, and in none of them was any scum 
ever formed upon the surface of the infusion. 
Examined microscopically, numerous Vibrios were found in the infusions of the 
straight-necked bulbs, many of them broken at the centre, with the two halves appa- 
rently trying to separate from each other. There were also numerous smaller Bacteria , 
very active and of various lengths. In the bent-necked bulbs a number of exceedingly 
small Bacteria were found, but no Vibrios. 
The deportment of the hay-infusion employed in these experiments corroborates the 
results of Dr. Roberts and Professor Corn. 
On the 2nd of October another infusion of hay was prepared, and, after neutralization 
with caustic potash, was introduced into six pipette-bulbs with straight necks. The 
necks, being first plugged with cotton-wool, were afterwards sealed by the blowpipe. 
The infusions were maintained for ten minutes at the temperature of boiling water. 
Their sealed ends were afterwards broken off, and they were subjected, like the former 
ones, to a temperature of 90° Fahr. 
Six other bulbs Avere charged at the same time with the same infusion ; but instead 
of being hermetically sealed, they were placed in an oil-bath, and boiled there for five 
minutes. Before the ebullition ceased, the neck of each was stopped with a plug of 
cotton-wool. 
Up to October 6th all the bulbs continued clear. On the 6th one bulb of the series 
last described became turbid, lighter in colour than its neighbours, and covered with a 
fatty scum. On the 7th one tube of the first series (boiled after the fashion of Roberts 
for ten minutes) also became turbid and exhibited the same fatty scum. The remaining 
ten bulbs maintained permanently their deep brown-sherry colour, their high trans- 
parency, and their perfect freedom from Bacterial life. They are still clear, though 
seven months have elapsed since their preparation. 
