308 DR. WILLIAM ROBERTS. 



purpose of isolating their individual temperature, and to 

 obviate, as much as possible, the disturbing effects of the 

 varying temperature of the room. For twelve hours no 

 change took place ; but, at the end of that time, a began to 

 ferment, and the thermometer marked a distinct elevation 

 of temperature. On the second day, a was in full fermen- 

 tation, and its temperature was 2'7 deg. above b and c. 

 This disturbance continued for five days, the temperature 

 ranging from two to three degrees above the companion 

 bottles. The disturbance than subsided, and the tempera- 

 ture fell to an equality with b and c, and a considerable 

 sediment, composed of yeast, settled at the bottom. In the 

 meantime, b showed little alteration; but, on the sixth day, 

 it began to ferment, the temperature went up, and for more 

 than a week its thermometer stood about two degrees above 

 a and c. Finally, the temperature in b declined, the dis- 

 turbance subsided, and the newly formed yeast settled to the 

 bottom of the vessel. 



This fever in a bottle resembled smallpox in the following 

 points. A period of incubation intervened between inocula- 

 tion and then commencement of disturbance ; then followed a 

 period of disturbance accompanied by elevation of tempera- 

 ture ; this was succeeded by a subsidence of the disturbance 

 and a return to the normal state. Great multiplication of 

 the infective material (or yeast) took place during the pro- 

 cess, and, after its conclusion, the liquid was protected from 

 further infection with the same contagium. We likewise 

 notice that the contagium of fermentation, like that of 

 smallpox, may take effect either by direct purposive inocu- 

 lation or by fortuitous infection through the atmosphere. 

 In both cases, the infective material has the power of pre- 

 serving its activity for an indefinite period. The compari- 

 son fails in at least one important point — in the fermented 

 urine, sugar is replaced by alcohol and carbonic acid ; but 

 we are not aware that any pronounced chemical changes 

 occur in the blood or tissues during an attack of smallpox. 

 I would, moreover, carefully guard myself against being 

 supposed to suggest that the enhanced temperature in the 

 fermenting urine is a real analogue of the preternatural heat 

 of fever. 



Let me direct your attention to another example — a kind 

 of partial decomposition or fermentation which takes place in 

 boiled hay-infusion when it is inoculated with the Bacillus 

 subtilis. The Bacillus subtilis is a very common bacterium 

 found in vegetable infusions and in curdling milk. I hope 

 you will take note of this little organism; for I shall have 



