RECENT RESEARCHES IN MINUTE LIFE. 
247 
easily destroyed. Thus they are unable to survive complete 
desiccation or a temperature higher than 80° C. On the other 
hand, it is equally well ascertained that masses containing bac- 
teria are not deprived of the power of originating new genera- 
tions of these organisms by heat, unless they are either subjected 
to a temperature considerably higher than that of ebullition, or 
boiled for a very long period. The reason of the apparent dis- 
crepancy is to be found in the fact that the bacteria have two 
modes of existence, the one characterised by permanence and 
resistance, the other by rapid development and short duration ; 
that in all bacterial masses which have the power of resisting 
high temperature ; e.g. in cheese, there exist, in addition to the 
ordinary forms of readily killed bacteria, other living particles 
of more stable structure. The properties of such bodies, to 
which Professor Cohn assigns the name of lasting spores 
(. Dauersporen ), are only just now beginning to occupy the 
attention of mycologists.” 
Dr. Sanderson is mistaken in supposing that fiC resting spores,” 
as they are commonly called, are only just beginning to occupy 
attention. It is ten years since Mr. Berkeley published a paper 
in the Intellectual Observer * 66 On the Resting Spores of certain 
Fungi,” in which many illustrations were given. It is quite 
probable that bacteria may produce resting spores, and very 
likely at certain stages of their existence a sexual process occurs, 
and the germs resulting from it have great powers of resisting 
heat. 
A confirmation of the views of Dr. Burdon Sanderson has 
just been obtained through the experiments of M. Feltz “ On 
the Poisonous Principle of Putrefied Blood.” f He found that 
even the powder of blood that had been putrefied to that stage 
in which bacteria, &c., perish, and then dried, could set up 
septicemic disease when mixed with water and injected into 
dogs’ veins. He concluded that germs of bacteria, which he 
could not detect with the microscope, had survived the putre- 
faction and desiccation, and were able to produce a new race of 
the infusoria. 
Where the germinating power of an ovule depends upon nitro- 
genous matter like common albumen, which coagulates and 
becomes insoluble at 60° C. (140° Fahr.), it is easy to under- 
stand why a temperature short of boiling kills it ; other nitro- 
genous bodies do not seem to lose their properties until actually 
burnt ; and it would not be surprising if organic germs should 
exist which can only be destroyed by a temperature at which 
wood becomes scorched. 
* Vol. vi. p. 31. 
t 11 Comptes Rendus,” May 31, 1875. 
