1899] FLOREAT WOOD'S HOLL 385 
portant part in developmental processes. In the fifth lecture Mr. A. L. 
Treadwell discusses equal and unequal cleavage in Annelids, in regard 
to which he seeks to show that equality of cleavage is not an indica- 
tion of lack of differentiation in the ovum, for definite cells appear at 
definite places and at definite times, just as accurately as in unequal 
cleavage. The sixth lecture, by A. D. Mead, is more technical, dealing 
with the debatable question of the origin and homology of the proto- 
troch. In the seventh lecture Miss Cornelia M. Clapp discusses the 
relation of the axis of the embryo to the first cleavage plane, and 
reaches “the only reasonable conclusion” that while the first cleavage 
plane may coincide with the median axis of the embryo, as Roux and 
others have shown, it is not a constant rule in any single case, much 
less a universal law. Dr. Thomas H. Montgomery, jun., recounts his 
observations on various nucleolar structures of the cell, and shows at 
least that both false and true nucleoli are structures of manifold com- 
plexity, in regard to which our knowledge is very vague. Dr. Watase 
follows with a lecture on protoplasmic contractility and phosphor- 
escence, in which he gently leads up to the conclusion that the true 
physical basis of phosphorescence finds its closest analogue in the 
common phenomena of heat-production, and is as extensive as life 
itself. Professor T. H. Morgan discusses in the tenth lecture some 
problems of regeneration, showing that it is not easy to solve them all 
by quoting Lessona’s law, or repeating the words “natural selection.” 
In the eleventh lecture Professor Bumpus, who has previously made 
good use of sparrows, shows that they are subject to discriminate elimina- 
tion. The twelfth lecture by Professor Jacques Loeb, on “The Here- 
dity of the Marking in Fish Embryos,” has been noticed separately. 
The late Mr. W. W. Norman, whose loss to science is deplored, 
was the author of the thirteenth lecture, which shows that reactions of 
lower animals upon injury furnish no safe evidence of pain-sensations. 
Professor W. B. Scott discusses North American ruminant-like mammals 
in his accustomed style, and then follows a fine essay by Professor 
W. M. Wheeler on Wolff and the Theoria Generationis. But, in some 
ways, the most impressive lecture is the last, in which Professor Whit- 
man discusses animal behaviour, and furnishes a notable contribution 
to comparative psychology. 
The charm of these lectures may be partly due to the circumstances 
of their delivery, but it is doubtless mainly due to the fact that each 
is an expression of personal work and personal interest. One cannot 
but be grateful to the Laboratory at Wood’s Holl, which has been the 
stimulus of the fine series to which this volume is added—Floreat 
Wood’s Holl. 
