494 Notices of Books. [October, 
this has never been done. The analytical method is equally 
powerless for the elucidation of the problem, for, as we have just 
said, in Dr. Bastian’s own words, the passage of dead molecules 
into living matter can never be demonstrated. The method 
therefore adopted is that of concomitant variations, and here it 
must be recollected that the several conclusions present, at the 
best, alternatives only. 
Direct microscopical examination of a liquid in which the 
lowest forms of life are prone to develope is considered to afford 
many data for the elucidation of the problem, though it is ad- 
mitted that the experience is not crucial. Dr. Bastian says, 
‘When a fluid containing an organic substance in solution is 
allowed to remain in contact with air, during moderately warm 
weather, it soon undergoes changes of a putrefactive or fer- 
mentative character.” It must be admitted, however, that this 
statement is too general. All solutions of organic matter are 
not susceptible of these changes. In those in which they do 
occur it is acknowledged that an invariable accompaniment of 
the changes is the appearance of specks of material, which in 
the course of a few hours are evidenced as minute, rapidly-moving 
bodies, known, for the most part, as Bacteria. It is urged that, 
as these have no demonstrable origin from visible parents in the 
fluid, they must, in all probability, have been formed out of the 
non-living ingredients. The current views as to the nature of 
these lowly organisms are very conflicting, and it must be ad- 
mitted that their life-history has yet to be written. It would 
appear, however, from morphological considerations, that they 
are not the simplest form which living matter assumes. The 
simplest organism with which we are acquainted is the Prota- 
moeba: this consists of a mere mass of plasma, apparently 
perfectly homogeneous and structureless, which multiplies by the 
mere separation of a portion of its substance from the parent 
mass: it is simply growing, moving, multiplying protoplasm. 
In a slightly higher form of Amceba the constituent protoplasm, 
instead of being perfectly homogeneous, is condensed in granular 
masses at various points, which become discharged from the 
parent as germs or ovules. It would seem that a bacterium 
presents still a higher differentiation: it is of a more definite, 
cylindrical shape; it moves with great rapidity in certain di- 
rections, forward or backward, and multiplies in some cases by 
fission, in others, as figured by Dr. Beale, who has examined 
these organisms with the highest powers yet employed—by ovu- 
lation. According to the view of the gradual evolution of the 
living from the dead, it would seem, prima facie, most probable 
that the simplest form—like the protamceba—should be first 
formed, and the bacterium differentiated therefrom. No observer, 
home has substantiated this view. 
In the description of the first appearance of living specks in 
an organic infusion Dr. Bastian’s observations closely follow. 
