106 
from the figures and inscriptions which they bore, 
and when in medieval times the art of gem- 
engraving was lost, the gems were still made 
serviceable by the representations of Greek deities 
being regarded as those of Christian saints, litur- 
gies being composed by means of which—the old 
love of ornament and mysticism remaining—the 
heathen relics were reconsecrated for Christian 
use. 
Of the persistence to recent periods, and even 
to our own day, of fanciful and superstitious 
beliefs concerning precious stones, Dr. Kunz gives 
many amusing illustrations. In a book published 
in Frankfort as late as 1718, an “airship” is 
represented which is raised by the supposed action 
of sunlight upon the “coral-agates”’ in its roof, a 
“magnetic action” being thus produced! Napo- 
leon, when in Egypt, found a carnelian seal 
engraved with Arabic characters, which he wore 
as a talisman until his death, and it was equally 
treasured and carried at all times by Napoleon 
III. The ill-fated Prince Imperial had it on his 
person in South Africa, and it appears to have 
been carried off by the Zulus who stripped his 
body. It is asserted that a well-known noble lady, 
still living, believes that her diamonds not only 
have life and sex, but are capable of reproduction ; 
while a recent trial in Paris showed that a wealthy 
lady became suddenly so overcome by fear of the 
evil influences of an opal-ring she wore that she 
slipped it off and put it on the finger of a poor 
girl who was passing. It is declared that a well- 
known authoress confesses that she habitually 
resorts to “crystal-gazing ”’ to recover the thread 
of a story that she has temporarily lost. 
Many very interesting extracts are given by 
Dr. Kunz from curious and little-known works, 
which illustrate alike the wildly absurd views held 
in all ages concerning the various influences 
exercised by different precious stones on those 
who wear them, and the cures and other wonders 
wrought by them, these ideas prevailing not only 
among the poor and ignorant, but among the 
educated of all classes and religions. The book, 
which is admirably illustrated, is as entertaining 
as it is instructive. TJ Wea 
” 
” 
ANIMAL MORPHOLOGY 
EMBRYOLOGY. 
(1) A Text-book of General Embryology. By Prof. 
W.E. Kellicott. Pp. v+376. (New York: 
Henry Holt and Co., 1913.) Price 2.50 dollars. 
(2) Zellen- und Gewebelehre Morphologie und Ent- 
wicklungsgeschichte. Unter Redaktion von E. 
Strasburger und O. Hertwig. Bearbeitet von 
E. Strasburger, W. Benecke, R. Hertwig, and 
@D) 
NO. 92306, VOL soa) 
AND 
NATURE 
{APRIL 2, 1914 
others. I. Botanischer Teil. Unter Redaktion 
von E. Strasburger. Bearbeitet von E. Stras- 
burger und W. Benecke. Pp. vii+ 338. Price 
to marks. II. Zoologischer Teil. Unter Redak- 
tion von O. Hertwig. Bearbeitet von R. Hert- 
wig, H. Poll, O. Hertwig, and others. Pp, 
Vii+ 538. (Berlin and Leipzig : B. G. Teubner, 
1913.) Price 16 marks. 
(3) Elementares Praktikum der Entwicklungs- 
geschichte der Wirbeltiere mit Einfiithrung in die 
Entwicklungsmechanitk. By Dr. Oscar Levy. 
Pp. vili+183. (Berlin: Gebriider Borntraeger, 
1913.) Price 5.60 marks. 
(t) HIS is an excellent book to place in the 
hands of intermediate students of 
zoology ; it gives a clear and interesting account 
of the more general aspects of embryological 
science. If the hypercritical reader regards it as 
somewhat scrappy and superficial, it must be 
answered that this is unavoidable in a book of its 
size dealing with so large a subject. The book 
does not pose as a work of reference; its function 
rather appears to be to give the student an idea 
of the present-day point of view of biologists 
towards the various problems of which it treats, 
to arouse his interest, and to direct his steps 
towards the fuller expositions to be found in con- 
temporary literature. 
An introductory chapter upon ontogeny is 
followed by excellent chapters on the cell and cell- 
division, the germ cells, and the process of 
maturation or meiosis. In regard to the last- 
mentioned phenomenon a very good and clear 
account of modern views is given. A few obvious 
slips will, no doubt, be corrected in a new edition, 
e.g., in the legend attached to Agar’s figure illus- 
trating the spermatogenesis of Lepidosiren the 
last six words convey an erroneous statement, and 
should be excised. Again, in the description of 
tetrad formation the student will be liable to be 
puzzled, if not misled, by the wording of the 
statement that “each of the newly-organised 
bivalent elements comes out in the form of four 
small bodies, the tetrads.””’ He may find himself 
in a similar position when he reads that in cases 
where tetrad formation takes place “the secondary 
spermatocytes have the diploid number.” Good 
accounts are given of fertilisation, and of the 
general features of segmentation, including “cell- 
lineage,” and these are followed by an excellent 
chapter on the differentiation of the embryo, 
heredity, and sex determination. In this chapter 
we welcome particularly the short and clear and 
critical account of the hypothesis of “ organ-form- 
ing substances,” which will act as a useful correc- 
tive to the somewhat prevalent teaching of this 
hypothesis by uncritical teachers as a well-estab- 
