1898] CURRENT LITERATURE 445 
selection of yeasts for the manufacture of beer and other liquors, a very 
much finer quality of bread may be secured, and many deleterious effects may 
be avoided. 
Further work was done to determine whether the yeast cells live in bread 
after baking, and the conclusion was reached that yeasts are always killed by 
the heat necessary to bake the bread. If living yeast cells were taken into 
the alimentary canal, however, they would probably produce no bad results 
as experiments made seem clearly to demonstrate. 
The papers contain most careful and interesting descriptions of the many 
kinds of bread and the best processes of making them.—OrTis W. CaLp- 
WELL, 
THE FLORA of Costa Rica has been receiving its share of attention, the 
results appearing in parts under the title Primitiea Flore Costaricensis. Parts 
I-III were published at Brussels in 1891, 1893, and 1896, respectively, under 
the joint direction of Th. Durand and H. Pittier. These three parts com- 
pleted the first volume, and at its close M. Durand was compelled to with- 
draw from the undertaking. The first part of the second volume has 
now appeared,5 published at St. José de Costa Rica, under the auspices 
of the National Geographical Institute, and with M. Pittier as sole editor. 
Mr. J. Donnell Smith has contributed the part by preparing a list of the 
known Polypetalz, including descriptions of new or recently described species, 
and omitting those families which have been presented in previous parts. It 
is a great gratification to those interested in the American tropics that this 
important publication is to be continued.—J. M. C 
PROTOPLASMIC streaming in Characee has been again investigated and 
is discussed from a strictly physiological point of view by Dr. Georg H6r- 
mann in an extended paper, independently published.” He seeks a theoreti- 
cal explanation of the movement of streaming and the ccppuregee of 
impulses. An explanation of the direction and plane of streaming, both in 
cells of the axes and rhizoids, Hérmann finds in the advantage of securing we 
shortest route from the places of absorption or manufacture to the pisert o 
utilization of the materials, which thus, in their transfer, are Sangeet to 3 
minimal loss. The larger part of the paper is devoted to a discussion 0 
experiments to ascertain the causes and nature of the movement, ~ e 
conduction of stimulation impulses. In his experimental work ee 
tion and ingenious adaptation of the modern methods of animal physiology 
yield new and valuable suggestions as to the theory of movement. 
*S PITTIER, H.—Primitiz Flore Costaricensis. Vol. Il, pp. 1-126. Polypetalae. 
by John Donnell Smith. San José de Costa Rica. 1898. $1.00. 
*6 HORMANN, GEORG,—Studien iiber den Protoplasmastromung bei den Characeen 
8°. pp. iv + 79. figs. 12. Jena: Gustav Fischer. 1898. 7/2. 
