380 BOTANICAL GAZETTE [NOVEMBER 
with the question of bacterial motility including all the vexed and difficult 
problems connected with the origin, distribution and significance of the 
flagella. There are important chapters upon growth and division and the 
formation of cellular unions or colonies, and upon spores and gonidia, and 
pleomorphism and variability. The ‘‘general part’’ comprised in the volume 
before us, and presumably to be supplemented some day by a “special part,” 
concludes with an interesting section upon the biological characteristics of 
bacteria, in which are discussed such phenomena as pigment production, 
anaerobiosis, parasitism, phosphorescence, the action of light and tempera- 
ture, and the special metabolic activities displayed by the sulphur, the iron, 
and the nitrogen bacteria. The merit of the whole treatise is that it brings 
together the information obtained through the researches of the past few 
years and presents it in a careful and lucid wa 
The author’s system of classification is state well known from its 
appearance something over a year ago in Die Natirlichen Pflanzenfamilien 
(Lfg. 129).3 It is simple and consistent, and at least does not include hypo- 
thetical genera to be hereafter discovered for the delectation of the scientific 
imagination. 
t may be questioned whether our author has made the best use of his 
space in threshing over the old facts of the historical development of classi- 
fication and nomenclature in the same thoroughgoing manner in which it has 
already been done. It must be confessed one is a little weary of seeing in 
monograph and text-book the same old “systems” trotted out for inspection 
again and again. The system of de Toni and Trevisan, for example, has 
certainly not proved such a help to bacteriology that we are justified in 
keeping it constantly before our eyes. Such systems are the flotsam and 
jetsam of progress, and if they are fain to sink of their own weight should be 
allowed to do so. The fetish of completeness, however, is conspicuous 
throughout the book, and much valuable space is sacrificed to it. The irre rrel- 
evant and the trivial do not deserve a place by the side of the significant and 
essential, and the writing of such a book as this should presuppose the selec- 
tion and sifting of material. 
The author's treatment of the cell nucleus question is, on the whole, dis- 
criminating and fair. He refuses to accept Biitschli’s statements as to tne 
existence of a Centra/kérper in bacteria, and denies that bacteria possess 4 
true cell nucleus “like the cell nucleus of higher plants,” but is inclined to 
look upon the metachromatic granules observed in the cell contents as 4 sort 
of primitive nuclear substance. 
Migula takes germination as the criterion of a spore, a process which ina 
true spore differs essentially from the proliferation of a vegetative cell, and 
on this ground gives no credence to the existence of arthrospores. He does 
3See Bot. Gaz. ar: 243. Ap. 1896, and American Naturalist, June 1896. 
maaroegt Mei eRe) a 
P 
3 
