574 
used in previous attempted introductions. 
In the spring of 1899, while traveling for 
the Section of Seed and Plant Introduction, 
I again sent winter caprifigs from Naples, 
and also, in considerable numbers, from the 
fig-producing regions of the mountains of 
Algeria. These also endured the journey 
well, and on arrival at Washington they 
were turned over to Dr. Howard, under 
whose direction they were liberated by Mr. 
Roeding in his extensive orchards at Fresno. 
This time the introduction was successful, 
and Blastophaga is now breeding in Cali- 
fornia, and, it is hoped, may pass the winter 
and become permanently established. 
The principal fig growing regions of North 
Africa, Italy, Greece, and Asia Minor were 
also visited in order to learn the methods 
of culture there pursued, and the conditions 
necessary to the life of the insect. In the 
spring of 1898, when the fig orchards about 
Smyrna were severely frozen, the ex- 
traordinary price of from one to three dol- 
lars a pound was paid for caprifigs from 
islands of the Archipelago and from Western 
Greece, to be used in restocking the orchards 
with the Blastophaga. From one to two 
cents a pound is the ordinary price of capri- 
figs. Some lucky owners of large caprifig 
trees realized fabulous sums for their crop, 
much more than would ever be obtained 
from a tree producing edible figs. 
Caprifigs are by no means all wild, as 
commonly supposed, but are extensively 
propagated and exist in several named and 
well-known varieties in Greece and Asia 
Minor. Itisfurther worthy of note that the 
proficht which are produced by certain trees 
often have a value greatly superior, and 
there is reason to suppose that some sorts 
produce not only more profichi, but more 
insects to the fig, and furthermore do not 
harbor the mess-mate, Philotrypesis ficaria, 
which is considered injurious by growers. 
I was shown a fig tree in Algeria to secure 
the fruits of which natives often journeyed 
SCIENCE. 
[N.S. Vou. X. No. 251. 
twenty or thirty miles. Another yielded 
proficht which sold in 1897, for seven dollars ; 
and in Patras, Greece, I saw a third tree 
which had brought inasmuch. These facts 
give some idea of the views of the natives 
as to the importance of the process of capri- — 
fication, which, indeed, all testimony agrees 
in proving to be absolutely necessary for secur- 
ing a crop in all figs of prime commercial 
value in the dried condition. 
WALTER T. SWINGLE. 
U. S. DEPT. OF AGRICULTURE. 
SCIENTIFIC BOOKS. 
Praxis und Theorie der Zellen- und Befruchtungs- 
lehre. By PROFESSOR VALENTIN HACKER. 
Jena, G. Fischer. 1899. 260 pp. 1387 Figs. 
The last decade has witnessed the appear- 
ance in a large number of biological laboratories 
of a new course of study, now becoming gener- 
ally known as cellular biology or cytology, 
which has created new demands in the way 
of text-books and laboratory methods. In its 
morphological aspect this study is nearly related 
to, and strictly speaking forms a part of, the 
older histology ; though a practical ground of 
distinction lies in the fact that cytology is princi- 
pally concerned with the anatomy of the cell 
considered as an individual, while histology in- 
cludes also the comparative anatomy of the 
tissues. Cytology covers, however, a much 
wider field than that of cell-anatomy, for a very 
important part of the study relates to the proc- 
esses of cetl-reproduction and cell-physiology, 
including the phenomena of cell-division, the 
maturation and fertilization of the germ-cells, 
the physiological relations of nucleus, cyto- 
plasm, and other cell-organs, and many cognate 
problems relating to growth and development. 
The subject thus becomes one of very wide 
scope, and indeed joins hands with every branch 
of biology that can be studied from the cell- 
standpoint. As practically taught, however, 
cytology is still largely occupied with cell-mor- 
phology and reproduction, and the historical 
development of the subject has been such as to 
concentrate the attention of cytologists to a 
considerable degree on the structure of the re- 
productive organs and on growth, division and 
