826 
but exceptionally complete discussions of the 
main relations between growth and the en- 
vironmental factors. Nevertheless, the treat- 
ment of the influence of temperature lacks 
any mention of the conception of the tempera- 
ture coefficient of growth activity, the chem- 
ical principle of Van’t Hoff and Arrhenius as 
recently applied to physiological phenomena, 
although the author emphasizes the point that 
the phenological method of summer tempera- 
tures for the growing period can not be ex- 
pected to give anything but the crudest of 
indications regarding the temperature rela- 
tion of plants. It seems that enough has al- 
ready been accomplished with the Van’t Hoff- 
Arrhenius principle to warrant some treat- 
ment in a work of this kind. In the section 
on the influence of light, Palladin points out, 
as he has done before in the literature, that 
many of the developmental phenomena which 
are usually ascribed to light conditions should 
rather be referred to those of moisture. “ All 
the characteristics of the development of etio- 
lated plants may be explained by the altered 
transpiration conditions of these plants and 
by the resulting correlative influences of the 
individual organs ” (p. 257). 
In the last chapter of the book the author 
very happily presents the modern theory of 
internal secretions (developed from work with 
animals) as the basis of the physiological 
control of growth. “ Hormones must doubt- 
less also exist in plants.” “The various phe- 
nomena of growth and of plant form will 
surely prove to be dependent upon different 
hormones” (p. 300). Such predictions, to- 
gether with the activity of animal physiolo- 
gists in this direction, can hardly fail to exert 
an accelerating influence upon the develop- 
ment of plant physiology. 
In a general way, as clear and readable a 
book on this subject has not previously ap- 
peared. The style is always simple and nearly 
always characterized by strict logical se- 
quence. The volume is almost without teleo- 
logical implications, though the purist on this 
subject may smile at such an obsolescent sec- 
tion heading as, “The Necessity for the 
Movement of Materials” (p. 122), and the ex- 
SCIENCE 
[N.S. Vou. XXXV. No. 908 
position thereof, which indicates that neces- 
sity here means need and not cause. Such 
must be regarded as mere slips into hitherto 
common and now more or less stereotyped 
modes of expression frequent im biological 
literature. The more fundamental principles 
are developed by the historical method, at once 
placing before the reader the present status of 
any given question and the names and meth- 
ods of the workers to whom that status is 
due. Citations of literature are numerous, 
but not too numerous, and the western reader 
will be gratified in finding here a source for 
references and digests of some of the more im- 
portant contributions not commonly cited in 
German, French and English works of this 
character. 
On the whole, the reviewer is inclined to 
place Palladin’s work at the head of the 
rather short list of books suitable to be placed 
in the hands of elementary students of plant 
physiology. 
Burton E. Livincston 
THE JOHNS HOPKINS UNIVERSITY 
Fourth Report of the Wellcome Tropical Re- 
search Laboratories at the Gordon Memorial 
College, Khartoum. Vol. A, Medical, 404 
pp., 23 pls., 118 figs. in text. Vol. B, Gen- 
eral Science, 333 pp., 20 pls., 101 figs. in 
text. ANDREW Batrour, M.D., Director. 
Published for the Department of Education, 
Sudan Government, Khartoum, by Bail- 
liere, Tindall and Cox, London; Toga 
Publishing Co., New York City, agents for 
the United States. 
These two highly specialized and elabo- 
rately illustrated volumes are filled from cover 
to cover with the results of research of high 
order. They are an epitome of the peaceful 
and effective conquest of the Sudan by the 
forees of modern science, of biology and 
chemistry, applied to the problems of the 
desert and the jungle in the tropics among a 
people submerged in ignorance and supersti- 
tion and sunk in racial lethargy. The army 
of occupation is small, the staff of these lab- 
oratories numbering but eleven, including two 
officers, Captains Archibald and Fry, detailed 
