846 THE AMERICAN NATURALIST. | [Vor. XXXIX. 
In one respect the volume falls short of what it might have been. 
Little or no attention is given to the phylogeny of tissues and while 
this aspect of the subject is necessarily chiefly theoretic, a broadly 
grounded treatment cannot afford to omit it. Aside from this the 
volume is most acceptable. The presswork is excellent and the 
numerous figures, many of which are in color, afford a most ample 
body of illustrations for the text. There is a very full table of con- 
tents and an excellent index. 
CH- P 
Studies in Heterogenesis.!— One hundred years ago, Oken be- 
lieved he had evidence that animal and vegetable tissues disintegrate 
after death to give rise by rearrangement of their elementary parts 
to minute living things which combine in larger and larger aggregates 
to form the myriads of infusion-dwelling microscopical organisms. 
Such an hypothesis is excusable with Oken in 1805, but in 1905, 
after more than sixty years of cell study, — after complete establish- 
ment of the dictum omnis cellula e cellula, the limit of toleration is 
overreached and we read with ever growing impatience the mass of 
so called evidence that dead protoplasmic substance is directly meta- 
morphosed into living organisms of diverse species, genera, and even 
kingdoms. 
This “evidence” is beautifully presented in 350 pages of letter 
press, with an appendix of 35 pages, and with 815 illustrations from 
microphotographs, by which, as the author tells us, the careful student 
can “help to break down the barrier of incredulity which at present 
excludes any general acceptance of the truth and universality of those 
processes of heterogenesis by means of which, as I believe, the lower 
forms of life, both animal and vegetal, are ever springing up anew in 
countless myriads from matrices wholly unlike themselves” (page 3). 
The photographs are fairly well taken and illustrate many common 
forms In stagnant waters but to present them as proof of heterogene- 
sis recalls the natveré of the small boy offering his pole and line as 
evidence of the ten-pound bass that escaped his hook. 
Without going too much into details here, we may sum up the 
author's pomt of view by the following results which he believes are 
proved by his “evidence ” : — 
; wo Aggregates of bacteria in the zoóglcea stage may be transformed 
nto i ; 
; ungus germs, or into Amaebze, Mastigophora, or even into ciliated 
nfusoria (pp. 65-108), 
' Bastian, H. C. Studies in Heterogenesis. 
; London, Williams and Norgate 
1903. Svo, ix + 354 + xxxvii pp., 19 pls. /6. en 
