268 
NATURE 
| Fuly 23, 1885 
Among the most important results of experiments are 
those connected with the effect of temperature and of 
chemical agents on the embryo; especially the very 
potent action of quinine and atropine on the primitive 
heart ; and the comparative inertness of strychnia, curarin, 
and hydrocyanic acid on the more advanced fcetus. 
These results, considered with those relating to the diffu- 
sion of sustances between mother and foetus, have a 
practical bearing on the medical use of the various drugs 
during pregnancy. No less important therapeutically are 
the effects of change of blood-pressure in the uterine 
vessels ; and a very practical though old question is fully 
discussed—namely, whether the umbilical cord should be 
divided early or late after delivery. 
In certain experiments the coagulation of blood from 
the embryo was observed to be very slow. It would be 
interesting if it were shown that coagulability is acquired 
only shortly before the birth of the animal, when it first 
needs this property of the blood to guard it against 
hemorrhage. 
The most interesting section of the book is that which 
deals with the secretions of the embryo. The experi- 
ments of the author and other observers are collated, 
with the result of showing the early appearance and 
activity of some of the digestive fluids, and the compara- 
tively late acquirement of the amylolytic faculty, particu- 
larly in the human species. The origin of the amniotic 
fluid is here discussed—how far it is derived from the 
maternal or from the foetal blood, and whether and 
to what extent the fcetal urine contributes to its 
formation. 
Prof. Preyer endeavours to find a satisfactory derivation 
for the word amnion. 
to connect it with duvioy, a receptacle for the blood of a 
victim in a sacrifice, with durds, a lamb, or other proposed 
sources ; so he suggests an origin from a-, and pévos, 
strength, because of the delicacy and lacerability of this 
membrane. ‘This may be physiological, but it is hardly 
philological. If we cannot be satisfied with the explana- 
tion that dyriov in either sense was something which 
appertained to a lamb, we may conjecture an earlier 
origin from the root am-, around, seen in dp-di, am- 
futare, and German wm, in which case éuvioy may mean 
a receptacle or envelope. 
There is no doubt that spontaneous movements of the 
embryo take place long before its maturity, and Prof. 
Preyer considers that muscular action occurs earlier than 
is generally supposed. He adduces the fact that the um- 
bilical cord has already begun to twist in the human 
embryo at the eighth week, and asks, “ How else could 
this take place, if not through the foetal movements?” 
Now it seems improbable that the muscular movements 
should be entirely or even mostly in one direction ; and 
therefore some more satisfactory explanation must be 
sought. 
to the excessive growth of the umbilical arteries, so that 
they are obliged to take a tortuous course: and, when a 
slight obliquity has once been established, every pulsation 
will tend to increase the spiral, and every movement of 
the foetus or of the mother will be taken advantage of ; 
the cord and foetus revolving together until, with the 
growth of the foetus, the friction of the amnion puts an 
end to the rotation. 
It does not appear to him possible | 
We would suggest that the twisting may be due | 
The section dealing with the senses of the embryo is 
scarcely less interesting than that on the secretions. In 
connection with this we find a discussion on the state of 
the nervous system before maturity: whether it be in a 
waking or a sleeping condition, or whether these con- 
ditions alternate with one another. 
Among the appendices is one, by Dr. R. Ziegenspeck, 
of Jena, treating of the foetal circulation. There are also 
several coloured plates illustrating the circulation and 
other subjects. The usefulness of the book is much 
enhanced by the addition of a list of the literature on the 
special physiology of the embryo. The books and papers 
in this list (552 in all) are numbered and indexed; and, 
whenever either of them is quoted in the text, its corre- 
sponding number is given in the margin for reference. 
F, J. ALLEN 
OUR BOOK SHELF 
The Animal Parasites of the Sugar Cane. By H. Ling 
Roth, late Hon. Sec. to the Mackay Planters’ Associa- 
tion. Reprinted from Szgar Cane, March and April, 
1885. (London: Tribner.) 
IT is within the knowledge of most people that when a 
matter of this kind is under consideration, there are never 
wanting those who are ready with suggestions—for the 
most part based upon a foundation anything but practical 
or logical. Quacks are always at hand with their “cures,” 
greedy for the gain which it is the object of their imposi- 
tions to intercept. Experience and common sense alike 
show that but two courses here lie open: either the cane- 
crop must be rooted up and something else substituted 
in its place, or the most searching inquiries must be 
instituted into the life-histories and conditions of existence 
of the organisms working the mischief. 
The value of any publication on such a subject must, 
from the above considerations, be proportionate to the 
extent to which it assists the farmer in dealing experi- 
mentally with his enemies. Looked at from this stand- 
point, Mr. Roth’s modest little pamphlet cannot fail to be 
of great service to the intelligent planter, for it embodies, 
together with the results of the author’s practical experi- 
ence, a bibliography of all that has been written on the 
subject. 
Planters are beyond doubt largely a conservative body, 
and it is well known that years ago when first the failures 
of the Ceylon coffee-crops became disastrous, the atten- 
tion of the grower was in vain directed to the tea-plant— 
then flourishing as an ornamental shrub in the gardens of 
certain residents. The deaf ear has since been opened,. 
and the mourning of the disappointed coffee-grower 
is now being turned into the joy of the successful tea- 
planter. Unfortunately the conditions of growth of 
the sugar-cane will not admit of so easy a solution of 
the problem as that available in the above cited case, 
but the refrain of the paper before us is more diology. 
Nothing whatever can be done until the world is fully 
familiarised with the life-cycles and conditions necessary 
for the existence of the said parasites. The success which 
has recently attended the study of the liver-rot among 
sheep may be instanced as an example of what can be 
done in the field of applied biology, and there are among 
us young and competent workers ready to take the task 
in hand should opportunity offer. 
The facts narrated on p. 2 of the paper are anything 
but encouraging to those who would seek Government 
| aid. Much can be done by Governments, and it may be 
that when corporate bodies realise that pests of the 
category of those now occupying our notice are formidable 
even as an armed force, they will see fit to turn attention 
to them. 
