116 
POPULAR SCIENCE REVIEW. 
in biology are learned, but not the lesson. And yet by the teach- 
ings of this complex and doubtful method alone Dr. Bastian 
is content to accept “abiogenesis” as a great fact in nature. 
To those who are best acquainted with the experimental history 
of the subject for the last twenty — but certainly for the last six 
— years this is the more remarkable. For the weight of evidence 
is certainly not only not in favour of “ abiogenesis,” but is in 
the strongest sense adverse to it. The most refined, delicate, 
and continuous researches all point to the existence of what are 
at present ultra-microscopic germs. This, indeed, is directly 
affirmed by the authors. A single and recent instance will 
suffice. After a remarkable series of experiments detailed before 
the Royal Society Dr. W. Roberts says : “The issue of the 
foregoing inquiry has been to confirm in the fullest manner the 
main propositions of the panspermic theory, and to establish the 
conclusion that bacteria and torulce , when they do not proceed 
from visible parents like themselves, originate from invisible 
germs floating in the surrounding aerial and aqueous media.”* * * § 
But further, this has been remarkably sustained by ana- 
logical evidence. There are putrefactive organisms that 
closely approximate to the bacteria in form, structure, and 
size. These are the “ monads ,” or, as Professor Huxley 
doubtless more fitly names them, the heteromita. f They 
live side by side with the bacteria in the same putrescent 
mass, and certainly in the later stages of the disintegra- 
tion of dead organic matter are the most active and power- 
ful agents. From their greater size they present a more 
promising field for microscopical research than the bacteria 
themselves ; and the life-history of some of these could be fully 
mastered. I long since felt that valuable aid might thus be 
rendered to the discovery of the nature of the bacteria. Armed 
with the best and most powerful appliances which the modern 
optician could supply, Dr. J. Drysdale and myself ventured on 
the work. The results are fully detailed elsewhere.^ It need 
only be remarked here that the only hope of success was in 
continuous observation of the same form, in the same drop of 
fluid, under the highest powers. The secret, therefore, was to 
find a means of keeping the same drop under examination 
without evaporation. This we did. § The result was that patient 
work enabled us to completely unravel the life-history of six 
of these organisms. These life-cycles cannot be here recounted. 
Suffice it now to say that each of them multiplied enormously 
* “Phil. Trans.” 1874, p. 475. 
t “Macmillan’s Magazine,” Feb. 1876, p. 879. 
% “Monthly Micros. Journ.” vols. x. xi. xii. and xiii. 
§ Ibid, vol. xi. pp. 67-69. 
