222 BOTANICAL GAZETTE [MARCH 
tiate the structures which are present.’’ He has discovered that material treated 
with a strong solution of iodin; then washed with g5 per cent. alcohol; finally 
placed in water and pressed upon and rolled under a cover glass gives prepara- 
tions ‘‘in many ways superior to microtome sections.”” Hence the many colored 
figures which accompany his paper are all drawn from optical cross or longi- 
tudinal sections rather than from microtome sections. Such a method appears to 
the reviewer entirely inadequate to solve the difficult problems pertaining to the 
cells of the Cyanophyceae. 
The central body, which is regarded by GARDNER as a nucleus, consists of a 
thread-like structure composed of chromatin (as evidenced by goers reactions); 
a ground substance (not differentiated in his drawings); and ‘‘a-granules” 
(the slime globules of former authors). The ground eee acts, in his opin- 
ion, simply as a matrix for the chromatin elements and plays no essential role in 
nuclear division; as to whether this is achromatin or not, the author withholds 
judgment. Three types of nuclei are distinguished: (1) the diffuse type, which 
is characteristic of most of the fifty forms examined; (2) the net-karyosome type, 
found only in Dermocarpa—which presents a new kind of nuclear division, in 
that a large nucleus is represented as breaking up simultaneously into a large 
number of daughter nuclei; and (3) the primitive mitosis type, found likewise in 
one species only. The nuclei of types 1 and 2 divide by simple amitosis; while 
in type 3 the breaking up of the oo thread into three long parallel seg- 
ments is regarded as a step toward mitosis. 
GARDNER finds no special Sans The first product of assimilation, 
in his opinion, is grape sugar, some of which is converted into glycogen and thus 
stored. He adds some interesting experiments on the effects of various changes 
of habitat, such as from salt water to fresh and to distilled water, alternate drying 
and submergence in water, the effect of prolonged darkness, etc. He finds that 
such changes do not produce any marked change in cytological characters. 
UILLIERMOND, who also apparently used no sections in his study, is in 
general agreement with GARDNER’s conclusions. He prefers, however, to regard 
the central body as a sort of nucleus reduced to the state of a ‘‘chromidial” 
network. It is in reality ‘un noyau sans membrane” (a conclusion which nearly 
all other investigators who accept the nuclear nature of the central body have 
held before him). Gur~~reRMOND comes to one conclusion, however, which is 
apparently new, namely that there are present in the central body two kinds of 
granules, whereas GARDNER as well as most other investigators have distin- 
guished only one. The one or two large, conspicuous granules of the central 
body GUILLIERMOND refers to the nucleolus-like bodies of A. MEYER (in my 
opinion the so-called slime globules). Besides these, he distinguishes the meta- 
chromatic granules; smaller numerous granules which he regards as correspond- 
ing to the slime globules (PALLA), or red granules (BUrscHLI), or anabaenin 
granules (FiscHer), or volutin granules (MEYER). Their appearance in some 
of his drawings suggests, however, what have been called by the reviewer, in a 
paper on the subject, chromatin granules. It seems likely, in fact, that GUIL- 
