1921] HELLER—BACTERIA 391 
(blue-green algae without nuclear membrane), placed the Bacte- 
riales as an order coordinate with two orders of the blue-green 
algae. Birscuit (6) and Kies (19) emphasized the common 
characters of the bacteria and the protozoa. 
Today the question is apparently no nearer a solution than it 
was forty yearsago. The various views are based on the considera- 
tion of different life manifestations. Close relationship between 
bacteria and protozoa, however, is no longer emphasized. The 
principal views held today are three: (1) that the bacteria are 
members of the group of fungi, (2) that they are derived from or 
closely related to the Cyanophyceae, and (3) that they are the 
primitive forms from which fungi and algae are derived. The first 
two opinions are held by morphologists. Those who have regarded 
the manner of division and sporulation, the external characters of 
the organism so to speak, and those who hold that bacteria possess 
a small oval or round nucleus, have allied the bacteria with the 
fungi. Others who have studied their nuclear structure have allied 
them with the Cyanophyceae. Chemists and general students of 
evolution have recently considered them as ancestors of the other « 
groups. 
The morphological field has been reviewed carefully by MEYER 
(21), who holds that the closest affinities of the bacteria are with 
the fungi. The bacterial nucleus, according to his conception, is 
similar to the nucleus of the fungi. SWELLENGREBEL (27), GARD- 
NER (13), and Dopett (11) have observed structures, which they 
believe to be nuclei, that have marked resemblance to the chromo- 
phyll portion of the central bodies of the Cyanophyceae. GUILLIER- 
MOND (15) and a number of other workers hold the bacterial 
nucleus to be ‘‘chromidial”’ or finely distributed in the cytoplasm. 
Dose tt finds structures resembling all these types, which he holds 
to. be nuclei, and he believes the bacteria to be related most closely 
to the Cyanophyceae. West (29) described a blue-green alga, 
Myxobactron, which shows no differentiation of its protoplasm. 
PARAVICINI (25) has recently described minute compact structures 
that he believes to be nuclei. 
JENSEN (18) rearranged the bacteria on a chemical basis, and 
defined their relation to the algae, fungi, and protozoa, presuming 
