118 ROYAL SOCIETY OF CANADA 



ochre-yellow. At 25°C. to 27°C. the colors were as above described 

 but the changes were more rapid and the period of pigmentation was 

 shortened. 



Saccardo's Chromotaxia Sen Nomenclator Colorum, Patavia, 1894, 

 was used as a color scale, the following colors were observed : 29, Ochre- 

 yellow; 30, Amber-coloured; 31, Rusty; 33, Yellow-green; 36, Smarag- 

 dine; 37, Verdigris; 30, Prussian blue; 41, Azure, bright blue; 42, Fal2 

 blue; 43, Eye-blue, eye-grey; 44, Lead-coloured; 46, Dark violet; 47, 

 Violet; 48, Lilac; 49, Livid; 50, Vinous. 



The Action of Chemicals on the Pigment. — The pigment was 

 extracted from agar cultures with 50<^ alcohol and the solution was 

 bright blue and wine color. The wine color was best seen by transmitted 

 light and at some angles the solution was violet. On adding an equal 

 volume of 95^ alcohol, the pigment was precipitated from its solution 

 in 50^ alcohol and the filtrate had a faint wine tint only. 



When an alcoholic solution was shaken with chloroform and allowed 

 to stand, the color was all in the alcoholic layer. 



The pigments from agar cultures were soluble in cold water, and 

 when the solution was shaken with ether, benzine or chloroform and the 

 mixture allowed to settle, the pigment was all in the water layer, nor 

 did these chemicals take up color when poured over pigmented agar. 



Chemicals had the same action on the pigments whether they were 

 dissolved in alcohol or water or diffused in agar or gelatin. The color 

 changes produced by acids and alkalis were best observed by removing 

 a piece of agar, which contained colonies rich in pigment granules, 

 from a plate culture to a glass slide, and then either placing this upon 

 a sheet of white paper or else on the stage of the microscope and observ- 

 ing with a low power. In all cases, the changes in color were compared 

 with the colors given in Saccardo's chart. 



Concentrated Acids. — HCL, HoSO^ and HlSTOs rapidly changed 

 the color from bright blue through violet, livid and dark violet to vinous. 

 The changes progressed from the surface inward and in the same way 

 faded through lilac and disappeared. Decinormal and dilute acids 

 caused the same changes but more slowly and with less intensit}', so also 

 did the organic acids — formic, acetic, butyric, lactic, oxalic, malic, and 

 citric. 



Alkalis, as normal NaOH, KOH, Ca(OH),, Ba(OH)o, and 

 NaaCOs, rapidly changed the original blue color to green-blue. With 

 the first two reagents the pigment grains dissolved with an intense 

 vinous color which changed rapidly to green-blue. The color then faded 

 through blue-green to emerald green and then disappeared. Decinormal 

 and weak alkalis produced these changes more slowly. 



