1895. ] Anatomical and Physiological Researches. 419 
variations in the different species, at least in many cases, bear 
a close relation to the conditions of growth; so that those 
species which are generally found in rapidly flowing water 
formed rhizoids under all conditions and the rhizoid forma- 
tion may be considered as a specific character. An entirely 
opposite condition exists in those species of Spirogyra which 
in no case formed organs of attachment (S. varians, Weberi 
and others not specifically named). Spirogyra fluviatilis and 
Vaucheria clavata may be regarded as a mean between the 
only, and he suggests that these might gradually have ac- 
quired this ability from species in which the necessity for 
rhizoids was originally wanting. This view confirms that of 
Klebs,? who suggests that V. clavata might be regarded as 
an offshoot of V. sess¢lis which has been removed from its 
accustomed habitat into rapidly flowing water. 
he experiments were conducted in the laboratory of Prof. 
Klebs of Basel and the results are published in pamphlet 
orm. Two plates illustrating the various results are ap- 
pended to the text. . 
The work gives evidence of careful thorough investigation 
and it will be read with interest by all who have made a study 
of these forms of alga. _-BERTHA STONEMAN. 
Investigations on bacteria.* 
The paper is divided into four parts, which treat respectively 
of plasmolysis of bacteria, physiology of motile organs, mor- 
Phology of cilia, and systematic bacteriology. 
In the first three parts, the author draws attention to many 
points of interest that he has observed in his studies, and dis- 
cusses the relation of the same to the different theories that 
have been advanced from time to time. 
. He brings further proofs to substantiate his earlier claim* 
that the bacterial cell is subject to plasmolysis like the higher 
plant forms. Plasmolysis frequently occurs in the prepara- 
tion of ordinary cover glass mounts where the evaporating 
*Zur Physiologie der Fortpflanzung von Vaucheria sessilis. Verhandl. d. 
naturforsch. Ges. in Basel 10: —. 1892. 
* Untersuchungen tiber Bakterien, Jahr. f. Wiss. Bot. 27: 1-163. 1895. 
*Ber. d. konigl. sachs. Ges. d. Wiss. —: 52. 1891. 
