586 
- the rate and amount of reproduction in water 
as they do upon land. 
The question of the biological stratification of 
the haliplankton is treated at length. Investi- 
gation has shown that the marine phytoplank- 
ton is mainly limited to a relatively thin super- 
ficial region about 200 m. in thickness and that 
it ceases to grow below 400m. The zooplankton 
on the other hand descends, in the opinion of 
many investigators, to greater depths, feeding 
upon the débris of the phytoplankton and 
upon cadavers, descending from the more 
densely populated zone above. The Valdivia, 
which made but few hauls at great distances 
from continental influence or away from 
great currents, found evidence in closing net 
catches of animal life extending to great 
depths. , 
Steuer’s presentation of Agassiz’s results 
and conclusions in this contested matter is far 
from adequate. He designates the Pacifie as 
“sehr planktonarme” and “wenig giinstig ” 
for the examination of this question of the ex- 
tent of life below 400 fathoms. The plankton 
of the Pacific is certainly as rich in large areas 
and probably no poorer in others than that of 
other oceans, while the oceanic conditions it 
presents for investigation could hardly be 
more typical or more favorable for the determi- 
nation of this question. Nor is Steuer’s state- 
ment that Agassiz’s admission of the existence 
of a true bathybic plankton is to be accepted 
as placing him in accord with his opponents, 
to be regarded as either adequate or critical, 
for Agassiz limited this bathybie plankton to 
regions of continental influence and to terri- 
tories below richly laden currents. Further- 
more, to characterize Agassiz’s discoveries of 
so-called deep sea animals, such as Pelago- 
thuria and fishes as “gelegentliche Auftret- 
ungen” of the bathybic fauna in the upper 
levels of the sea is to dismiss a mass of evi- 
dence with a wave of the hand. 
The horizontal divisions and the geograph- 
ical and seasonal distribution of the plankton 
are discussed at length and its relation to the 
economy of nature and to man are analyzed. 
Under the latter caption attention is called to 
the relation of those occasional outbursts of 
SCIENCE 
[N.S. Vou. XXXV. No. 902 
species resulting in discolored seas and dis- 
turbances in the balance of nature, to plank- 
ton as a source of food for man and for fishes, 
to pond culture, to purification of polluted 
streams, to fish culture, to plankton as an in- 
dex of productive capacity of water, and to 
the relations of plankton organisms to educa- 
tion, research and the fine arts. 
A compiled work of this sort, the first in its 
field, is necessarily incomplete and imperfect. 
Noticeable omissions in both works are the 
Lucas sounding machine, Whipple’s thermo- 
phone, Nathanson’s discussion of the relation 
of vertical circulation to the problem of main- 
tenance of fertility of the sea, Petterssen’s, 
Ekman’s and Nansen’s contributions to facts 
and theories of oceanic circulation, Bauer’s 
work on vertical migrations, and, in general, 
an occasional lack of perspective in dealing 
with the results of Scandinavian, English, 
French and American literature of the sub- 
ject—defects easily remedied in a new edition. 
Dr. Steuer has done a great service in putting 
in so concise and compact a form the most 
striking and many noteworthy achievements 
in the field of planktology. The illustrations 
are numerous, usually good and well-executed. 
Exception may be taken to inverted figures of 
Ceratium (p. 476) and to an inverted figure 
from Okamura of a crushed Peridinian 
labelled Gonyaulax polygramma. Much bet- 
ter figures of this species have long been avail- 
able. 
The second work is an abridgment of the 
first, omitting some of the illustrations, the 
extensive bibliographies and some of the more 
technical treatment of the chemistry and 
physics of water and some of the details of 
the discussion of the seasonal distribution of 
the plankton. 
: Cuartes Atwoop Koromw 
UNIVERSITY OF CALIFORNIA 
The Realm of Ends or Pluralism and Theism: 
The Gifford Lectures Delivered in the Uni- 
versity of St. Andrews in the Years 1907- 
1910. By JAmMEs Warp, Se.D. (Camb.), ete., 
Fellow of the British Academy and of the 
New York Academy of Sciences, Professor 
