166 J. Wyman on living organisms in heated water. 
air at the ordinary temperature, added to the absence of the 
other signs of life, must be considered as the best indication of 
eath. 
1. Arrest of motion—The temperature at which motion ceases 
was determined as follows: a wide-mouthed bottle cone 
infusoria was set in a water-bath, and a thermometer suspen 
with its bulb in the infusorial fluid. The whole was gradually 
heated, and drops of the fluid were examined from time to time 
with the microscope, until the motions of the infusoria ceased. 
The following table gives the result of the examination of fluids 
taken from several different sources. The movements of the 
Vibrios lasted longer than those of all other kinds, and the tem- 
rature given below is that at which thé motions of these were — 
arrested. The motion of all the ciliated infusoria stopped at less 
than 180° F. 
EXPERIMENTS. 
Motion ceased bt thc [| MR aVick Ve Average. 
3 B a ° ° | ° ° ° eee ° F 
In infusoria from a macerating tub at/57°5|57 O/PO"V/9 CU/OO'UDG tw = 13406 . 
In infusoria from another tub at 550 570/58 0|57°0/58°0'56-4 C. = 138" F 
In infusoria from beef juice at 55°0/54-0/55°0/540! 54-5 C. = 13000 FB 
In infusoria fi tstated at|57-0|55-0/56-0| | [56-0 0. = 18290 F. 
2. Arrest of growth and reproduction.—In the following expel 
iments as a matter of convenience the temperature was always 
carried to the boiling point, though it by no means follows that 
is was in all cases necessary. The object was to determine by 
comparative experiments, whether the growth and reproduction 
of the infusoria and their reaction upon a given solution 1s a 
rested or modified by their having been exposed to a 
ment of infusoria. Equal quantities of the solution were pou 
into a given number of bottles, and these were divided into 
series. Those of the first were set aside as criteria; 1 
tween the effect of adding boiled or unboiled infusoria on the 
_ * In some of the later ex; : ; 
cilia of Doves * ie instead of beef juice prepared as above 
