Bae BOTANICAL GAZETTE [OCTOBER 
of chemicals. And, being entirely mechanistic, it has the great merit of offering 
the possibility of experimental advancement toward a complete solution of 
the problems of individuali 
he three succeeding chaptiics present some of the evidence which supports 
this conception of the origin and nature of individuality. The third chapter 
resents the evidence for the existence of metabolic gradients. This evidence 
consists mainly in the demonstration of susceptibility, ages and electric 
potential gradients in the organism coinciding with the supposed metabolic 
gradients. Em Ryologices ee vate e gd the existence ot axial metabolic 
gradients, and th ents in cases of asexual and experimental 
reproductions are considered. The evidence is varied and extensive, and comes 
— a —— of both animals and ‘Platits. ep a ‘et in showing that axial 
gr f organic constitution. 
Chap. iv considers the evidence for the existence of physiological dominance 
in the process of individuation, in support of the conception that “the organic 
individual is fundamentally a dynamic relation of dominance and subordination, 
associated with and resulting from the establishment of a metabolic gradient 
or gradients.’ The evidence is obtained principally from experimental repro- 
duction in plants and animals, and demonstrates the independence of apical 
regions in the developmental process, and the control of the development of 
other levels of the major axis by this independent apical region. The apical 
regions are the regions of most rapid metabolism, and they are physiologically 
dominant over the other subordinate levels. 
Chap. v gives evidence bearing upon the problems of range of dominance, 
physiological isolation, and experimental reproduction. The experiments deal 
with the control of the spatial relations of parts and of the range of dominance 
by altering the length of metabolic gradients; the obliteration and redeter- 
mination of axial gradients; the extension of dominance during development; 
and physiological isolation and reproduction in plants. The final chapter is a 
general discussion of individuality from the new viewpoint, and considers such 
topics as the nature of dominance and inhibition, the origin of metabolic gra- 
dients and dominance, the relation of morphological differentiation to metabolic 
rates, the fundamental reaction system (protoplasm), the nature of agamic 
and gametic reproduction, and closes with a brief but trenchant discussion of 
such large problems as heredity and nore from the dynamic standpoint. 
An interesting contrast is drawn between animals and plants in discussing 
the fundamental reaction system. In pens the independent self-determining 
apical region begins the process of differentiation, and if the self-determined 
changes go far enough, they result in the formation of a nervous system, physio- 
logically the most stable structure of the whole animal body. The greatest 
differentiation occurs in the region of highest metabolic rate. But in the plant 
the apical region remains undifferentiated, and the degree of differentiation 
increases with increasing distance from the ‘apical point, a situation exactly 
the reverse of that found in animals. This difference between the animal and 
