Micro-organisms of M \ n.i-: Sap 551 



Aqueous fuchsia. — Aqueous fuchsin was prepared by dis- 

 solving one gram of Griibler's fuchsin in jo cc. of water, 

 films from 4 day agar colonies of the 13 strains were treated 

 with this stain for two minutes and washed in water. The films 

 were mounted in water and microscopic examinations made. 

 The cells of Ps. fluorescens, Ps. longa, Ps. tenuis, CXV, CXL, 

 and LI were deeply stained: while those of Ps. alba, Ps. mesen- 

 teric^ Ps. putrida, CXII, CXLV, CXLV11I. and XXXV] were 

 only faintly stained. The cells from all strains except CXV pre- 

 sented a granular plasmolysed appearance and with strains Ps. 

 tenuis and CXL a bi-polar staining was common. 



Aqueous gentian violet. — The stain was prepared by dis- 

 solving 1 gram of Griibler's gentian violet in 10 cc. of water. 

 Preparations from 4 day agar colonies were stained 2 minutes 

 and washed in water. The cells of Ps. alba, Ps. longa, CXV, 

 CXL, CXLV, CXLVIII, and LI were well stained, while those 

 of Ps. fluorescens, Ps. tenuis, Ps. mesenterica, Ps. putrida, 

 XXXVI, and CXII were rather faintly stained. Plasmolysis 

 occurred with all strains but was particularly noticeable in the 

 following: Ps. fluorescens, Ps. longa, Ps. tenuis, Ps. putrida, 

 and CXII. 



Carbol fuchsin {Ziehl). — Films were prepared from 4 day 

 agar colonies of all strains, stained two minutes with Ziehl's 

 carbol fuchsin and rinsed with water. Strain CXV was the 

 only organism in which the entire cell was stained. Cells of 

 Ps. alba, Ps. fluorescens, Ps. longa, Ps. putrida were only faint- 

 ly stained, while those of Ps. mesenterica, Ps. tenuis, CXII, 

 CXL, CXLV, CXLVIII, XXXVI, and LI were fairly well 

 stained but showed a bi-polar effect. Chains of cells of the lat- 

 ter two mentioned strains presented a barred appearance. 



II. Cultural Fkatukks 



1. Agar stroke. — On agar stroke the thirteen strains dis- 

 played similar growth characters, indeed 110 specific constant dif- 

 ference can he pointed out. The line of inoculation first ap- 



