1910-11.] 
New Genus of Iron-bacteria. 
499 
XXXII. — On the New Genus of Iron-bacteria, Spirophyllum fer- 
rugineum (Ellis). (A reply to criticism.) By Dr David Ellis, 
Lecturer in Botany and Bacteriology, Glasgow, and West of 
Scotland Technical College, Glasgow. (With Two Plates.) 
(MS. received March 9, 1911. Read February 20, 1911.) 
In 1907 I had the honour of reading a paper before this Society in which a 
new genus of iron-bacteria was described. * This organism was first discovered 
in Renfrew, near Glasgow, and subsequently observed in various samples of 
iron-water from different parts of the country. At Renfrew this organism 
was at the time of its discovery the sole bacterial occupant of the iron- 
waters of this neighbourhood. In most samples of these waters — and I 
have examined hundreds. — only the remains of iron-bacteria can be obtained, 
but occasionally the samples are found to contain iron- bacteria in process 
of growth and multiplication. After a little experience, it is possible to 
ascertain which streams contain iron-bacteria in this favourable condition. 
At Renfrew such streams were then common, and so gave me an opportunity 
of tracing the life-history of this species. The results of this investigation 
seemed to me to justify the conclusion that I had obtained a new genus of 
iron-bacteria. In 1910 Professor Molisch’s book on the iron-bacteria was 
published,]- and in it he expresses the opinion that Spirophyllum ferrugineum, 
the name which I had given to this new species, was none other than a 
form of Gallwnella ferruginea. The object of the present paper is to support 
the conclusions of the former paper, and chiefly to supplement them by the 
publication of some photomicrographs which were taken at the time, though 
not published. I am indebted to Mr Robert Garry for the excellent nega- 
tives which he took for me. 
In the first place, I should like to note that my experience of the iron- 
bacteria has shown that their multiplication is spasmodic and short-lived. 
In Great Britain, at any rate, the iron-streams are usually devoid of living 
iron-bacteria, though there are plenty of remains in the sediments. Occa- 
sionally, however, as I have proved by my own observations and those of 
a band of assistants, here and there a zone of growth, local in its extent, 
* Ellis, “ On the Discovery of a New Genus of Thread Bacteria (Spirophyllum ferrugi- 
neum, Ellis),” Proc. Roy. Soc. Edin ., vol. xxvii., part i., No. 6. 
t Molisch, Die Eisen-bakterien ; Gustav Fischer, Jena, 1910. 
