424 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Coccogoneae. 
Chroococcacem. 
Chamassiphonaceae. 
Hormogonieae. 
Psilonematese. 
Oscillatoriaceae. 
Nostocaceae. 
ScytonemaceaB. 
Stigonemaceae. 
Trichophoreae. 
Rivulariaceae. 
CamptotrichaceaB. 
The artificial separation of the HormogonieaB into Homocysteae and 
Heterocysteae is abandoned. In the Psilonemateae — distinguished from 
the TrichophoreaB by the absence of the terminal hair — the first charac- 
ter used in differentiating the genera is the occurrence or not of branch- 
ing in the filaments. Plectonema is therefore placed among the Scyto- 
nemaceae, Isocystis and Microchsete among the Nostocaceae. The Cha- 
msesiphonaceae are placed among the Coccogoneas because of their uni- 
cellular structure up to the time of the formation of the conids. 
0. Schizomycetes. 
New Genus of Bacteria.* — Mr. A. Y. Jennings describes a genus 
of bacteria (. Astrobacter ) found in stagnant water in the neighbourhood 
of Tubingen by Mr. Coppen Jones. The specimens described were ob- 
served in preparations of Spirillum undula stained to show the cilia. 
The appearances depicted in the illustrations show rod, Y-shaped, an( j 
stellate forms, the latter having 4-8 rays. 
Decline and Regeneration of Spore-formation in Bacteria.f — 
Herr W. Migula states that it has been borne in upon him that the 
principal cause of the decline in spore-formation lies less in nutritive and 
environmental conditions, than in peculiar individual characters connected 
with the laws of inheritance. Hence the more any race or stock of any 
bacterium betrays an inclination to the vegetative form, the more this 
tendency will develop by continued cultivation ; and, per contra, the more 
such stocks or races incline to spore-production, the more probable is it 
that future sub-cultivations will exhibit the tendency to a freer and 
more constant development of spores. In order to test experimentally 
the accuracy of this hypothesis, the author selected a sample of anthrax 
with poor spore formation. A four weeks old culture on potato, which 
showed only a few isolated spores, was exposed for a quarter of an hour 
to a temperature of 90° C., to destroy the vegetative cells. Transfers 
were made on agar, and from these colonies potato was inoculated. This 
procedure was repeated several times, and in the end an anthrax culture 
was obtained in which each individual cell contained a spore. 
Method for Determining the Specific Gravity of Bacteria.^ — Herr 
Almvist has determined the specific gravity of bacteria by centrifuging 
* Proc. Roy. Irish Acad., v. (1899) pp. 312-6 (2 pis.). 
f Zeitschr. f. angew. Mikroskopie, v. (1899) pp. i-3. 
X Zeitschr. f. Hygiene u. Infekts., xxviii. (189S) pp. 321-30. See Centralbl. Bakt. 
u. Par., xxv. (1899) p. 619. 
