Life History of Monads. By W. H. Ballinger J. Drysdale. 197 
perature resisted, with no injury to the developmental power, by 
the sporules of the monad now described. 
Thus it will be seen that in no instance was the continuance of 
the species maintained without the introduction of a sexual process, 
a blending of what are shown in the sequel to be genetic elements, 
and thus going farther to suggest caution as to the supposition that 
any organism can be perpetuated by the mere self-division of single 
individuals. 
Our heating experiments have uniformly proved the fact that 
the spores resulting from sexual generation have a power of resist- 
ance to heat over the adult which is greater in the proportion of 
11 to 6 on the average, and this appears to us to be the very essence 
of the question of Biogenesis versus Abiogenesis. In some, at 
least, of the septic organisms spores are demonstrably produced, and 
these spores can resist a temperature nearly double that of the 
adults on the average ; and that which some can resist is 88°Fahr. 
above the boiling point of water. All this is in general harmony 
with the admirable experiments of Dr. W. Roberts,* as well as 
with the later ones of Huitzinga,t who could not destroy the bacteria 
or their germs by boiling under a heat of 230° Fahr. continued for 
half an hour. 
* ‘Phil. Tia:is.,’ 1874. 
t ‘ Academy,’ March 13, 1875. 
