VITALITY OF PUTREFACTIVE ORGANISMS. 141 



pulation pursued in the two cases. For it is 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 deport- 

 ment. Unlike the thick cloudiness of their neigh- 

 bours, 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 

 apparently trying to separate from each other. There 

 were also numerous smaller Bacteria, very active and 

 of various lengths. In the bent-necked bulbs a num- 

 ber of exceedingly small Bacteria were found, but no 

 Vibrios. 



The dejportment of the hay-infusion employed in 

 these experiments corroborates the results of Dr. 

 Roberts and Professor Cohn. 



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 tem- 

 perature 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 were 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 



