JOURNAL 



OF THE 



ROYAL MICROSCOPICAL SOCIETY. 



JUNE, 1914. 



TRANSACTIONS OF THE SOCIETY. 



VII. — Some Observations on the Morphological Changes occurring 

 in Beggiatoa alba on Staining by various Methods. 



By E. Moore Mumford. 



{Bead March 18, 1914.) 

 Plates VI, VII. 



Having occasion to attempt to prepare some stained preparations 

 of Beggiatoa alba Winogradsky for photographic reproduction, the 

 author experienced considerable difficulty in obtaining a stained 

 preparation of a typical thread. 



On fixing and staining by the usual bacteriological methods, it 

 was found that the sheaths suffered morphological changes and 

 completely altered in appearance, resembling indeed the higher 

 bacterium Sphwrotilus. 



Experiment, however, showed that the changes occurring in 

 the sheath were not only conditioned by the fixing by heat and 

 the staining with dyes such as gentian-violet, but that the deciding 



EXPLANATION OF PLATE VI. 



Fig. 1.— Strand of Beggiatoa alba (x 750). Collapse of cells, the matter in which 



still exhibits granulation. There is a distension of the sheath between 



the cells. 

 „ 2. — Strand of Beggiatoa minima Winogradsky ( x 1000). Typical appearance. 



From a creamery effluent. 

 ,, 3. — Strand of Beggiatoa alba (x 1000). Collapse; no granulation visible; 



distortion of sheath between the collapsed cells. From sulphuretted 



hydrogen water culture. 

 „ 4. — Strand of Beggiatoa alba (x 1000). Typical appearance. From natural 



stream growth transferred to sulphuretted hydrogen. 



June 17 th, 1914- R 



