FUNGI 273 



Phytophthora infestans, Uromyces caryophyllmiis, Puccinia graminis, 

 and many others. 



We should suggest phloxine instead of "Magdala red" since the 

 Magdala red which succeeds is probably phloxine. 



A method by Stoughton produces a fine differentiation in many 

 cases. He used it, originally, for Bacterium malvacearian in a study of 

 the disease which it causes in cotton. The stain is thionin and orange 

 G. The thionin was made as follows: thionin, 0.1 g., 5 per cent solu- 

 tion of phenol in 100 c.c. of distilled water. The orange was dissolved 

 in absolute alcohol. Schedule for paraffin sections: 



1. Stain in thionin, 1 hour. 



2. Through grades of alcohol to 100 per cent. 



3. Differentiate in a saturated solution of orange G in absolute alcohol, 

 about 1 minute. 



4. Wash thoroughly in absolute alcohol. 



5. Xylol-alcohol. 



6. Xylol. 



7. Mount in balsam. 



The parasite should be violet-purple; cellulose walls, yellow or 

 green ; lignified walls, blue; chromosomes, blue; and spindle, purple. 

 Freehand sections may be stained very quickly: 



1. Sections in water. 



2. Stain in carbol-thionin, 5 minutes. 



3. Wash in water. 



4. Ninety-five per cent alcohol. 



5. Differentiate in orange G, several minutes. 



6. Wash well in absolute alcohol. 



7. Xylol. 



8. Mount in balsam. 



We should suggest that, to get the best results, different stains may 

 be necessary for different forms. It would be worth while to experi- 

 ment. If the host is woody, select a good stain for xylem. Safranin is 

 generally good. Then try various blue and green stains until you find 

 one which suits that particular case. Or, take iodine green for the 

 xylem, and try various red stains for the fungus. If the host has cellu- 

 lose walls, try Delafield's haematoxylin or light green or anilin blue for 

 the host, and find a red stain for the fungus. 



