1897.] The Advance of Biology in 1895. 789 
four cells arising from the o6goumni—a rudimentary genera- 
tion corresponding to the rudimentary sexual generation of 
angiosperms—and a non-sexual generation, which comprises 
the soma, each of whose nuclei has double the number of 
chromosomes found in the sexual generation. 
Correlation—The development of the doctrine of internal 
secretions was the most important contribution of this year to 
the theory of correlation. Especially were the effects on other 
_ organs of the removal of the sexual glands, the thyroid, the 
superrenals, and the digestive glands carefully studied; and 
the obliteration of these effects, by feeding extracts of the tis- 
sues, observed. The specific action of one part of the organism 
upon the other parts was being unravelled. 
General morphology and physiology—This year witnessed the 
memorable discussion between A. Sedgwick and Bourne as to 
the morphological value of “ cells,” which served to emphasize 
their physiological significance. To the subject of budding we 
have the contributions of Chun, who showed that, in the me- 
dusæ, both layers of the bud may be derived from one layer 
only (the ectoderm); thus another blow was dealt to the germ 
layer theory. 
Especially memorable was the year for the appearance of 
Verworn’s “Allgemeine Physiologie,” which, in one leap, gave 
Scientific standing to that subject, and of LeDantec’s “La 
matiére vivante,” much less extensive, but in the ground it 
covers, more profound ; both works are dominated by the idea 
of the chemical nature of vital phenomena. The numerous 
papers on general physiology related to various subjects, es- 
pecially general cell-physiology, muscle contraction, phagocy- 
tosis, effect of external agents on organisms, geotropism 
(Czapek), heliotropism, thermotropism (Mendelssohn), nutri- 
tion, cell respiration (Loeb and Hardesty), immunity, toxines 
and ferments. 
Heredity —The year saw much discussion of the inheritance 
of acquired characters and the theory of heredity, but little 
Progress. The experiments of Charrin and Gley afforded 
another example of transmission (but rare and incomplete) to 
the first generation of the effects of vaccination. Hyatt pub- 
