596 



Journal of Applied Microscopy. 



wheat and oats are refracton- objects to cut. The cutting is easier after picro- 

 acetic acid than after corrosive sublimate or the chromic acid series. 



Evers- class whicli studies the rusts should attempt to germinate the uredo- 

 spores and teleutospores. For this purpose the hanging drop culture ma\- be 







c 



^-'•H^ 





Ir 



B 





jeUiAPPMC 



Fig. 52. Puodnia graminis. 



-•V. Transverse section ot BarbeiT\- leal showing 3e<idLa and $penn<igonia. X 7. B. Longitudinal section .if 

 a single ^ecidium. - iq2. Fixed in Flemming's weaker solution and stained in Delaiield's hsm,^- 

 toxylin. C. .\ single spemiagoniuni . s i<^. Fixed and stained as in B. D. Three 

 uredospores growing on oats. ■ 575. Fixed in two per cent, formalin, stained in 

 bulk in alum carmine, and teased .out in glycerine. E. Section of young 

 teleutospores 00 oats. - 375, Fixed in picro-acetic acid and 

 stained in cyanin and erythrosin. G, F, H. Three ripe 

 teleutospores fnom a leaf of oats showing \-ariation 

 inform. ■ 375. I. Germinating teleuto- 

 spores. 375. 



employed. Cement a rubber or zinc ring to the slide, or simply smear the lower 

 surface of the ring with vaseline and press it tightly against the slide : smear the 

 upper surface of the ring with vaseline, and over it invert the cover-glass with a 

 shallow drop of water containing the spores. (Fig. 33.) The uredospores 

 germinate readily all summer, but it is said that the teleutospores will germinate 



