872 THE AMERICAN NATURALIST. [VoL. XXXII. 
light is transformed into the specific, assimulative energy by 
chlorophyll. Tschirsch showed that chlorophylland hemoglobin 
probably originate in the same fundamental substance. The 
question of the process of albumen formation in plants was a 
burning one. Internal secretions attracted ever-increasing 
attention. Our knowledge of the réle and physics of osmosis 
in organisms and the action on organisms of light, electricity, 
(Loeb, Verworn), and chemical substances received important 
additions, as did also phygocytosis and the action of ferments. 
Heredity.— The year revealed an increased tendency towards 
experimentation: Boveri’s evidence for a hybrid without ma- 
ternal characters was almost annulled by the opposing investi- 
gations of Seeliger. In the matter of inheritance of acquired 
characters new experiments by Charrin and Gley indicated the 
inheritance of immunity. Loeb, testing the hypothesis that 
the nervous system acts as an intermediary between soma and 
germ cells, finds that the amphibian larva develops normally 
even after the axial nervous system has been severed. Very 
noteworthy is the fact that Ewart repeated Lord Morton’s 
experiment in telegony with somewhat confirmatory results. 
Variation.— The quantitative study of this subject has made 
good progress. Pearson investigated the mathematical laws of 
regression, heredity, and panmixia. Ludwig, Amann, Warren, 
and Thompson applied the quantitative methods to the variation 
of various species. Agassiz and Woodworth found the varia- 
tions in a medusa — Eucope — only such as are normal in 
other species. The great variation in embryonic as compared 
with adult stages was gaining more general recognition. 
Origin of Species. — The principal papers of the year were 
speculative. Weismann added to his system the conception of 
a struggle in the germ plasm by which those determinants 
which gain a slight advantage over their. fellows soon get the 
upper hand. The theory of mimicry was strongly attacked (¢.g» 
by Piepers, after many years of observations in the Malays). 
The struggle around the theories of natural selection and the 
utility of specific characters continued. Many cases of consid- 
erable variations due to environment, forming probable starting 
points of species, were described. 
