20 



BULLETIN 227, TJ. S. DEPARTMENT OF AGRICULTURE. 



Fomes annosus: In one week, the radial growth of the check was 15 mm.; 0.05 per 

 cent, 20 mm.; 0.1 per cent, 15 mm.; 0.15 per cent, 3 mm. In four weeks concentra- 

 tions up to 0.15 per cent showed 20 to 30 mm. ; 0.2 per cent, about 2 mm. Thus, the 

 rate of growth on 0.05 and 0.1 per cent concentrations equaled or exceeded that of the 

 checks, but the higher concentrations produced a decided inhibition. The growth 

 on the toxic media appeared very much as on the check. 



Fomes pinicola: In two weeks, the radial growth of the check was 40 mm. ; 0.05 per 

 cent, 9 mm. ; 0.1 per cent, 4 mm. ; no growth on 0.15 per cent. After four to six weeks, 

 no growth on 0.15 per cent. The growth on the toxic media was fluffy, white, and quite 

 similar in appearance to that on the check. 



Zinc chlorid. 

 (PL IV, figs. 53 and 54.) 



[Laboratory sample No. 2239. Cooperator, Grasselli Chemical Co., Cleveland, Ohio. Commercial salt, 

 meeting the specifications of the American Railw ay Engineering and Maintenance-of-Way Association.] 





Tests. 



Times 

 killing 



Concentration of the preservative (percent). 



Fungus. 



Num- 

 ber. 



Dura- 

 tion. 



point 

 veri- 

 fied. 



0.2 



0.2 



0.3 



0.4 



0.45 



0.475 



0.5 



0.6 



0.65 



0.7 



0.75 



Check. 





33 

 33 



Weeks. 

 5 to 8 

 4 to 8 



1 

 2 



4 



1 



1 



1 1 



1 















4 



F. pinicola 



4 



4 



4 







i 

















Fames annosus: In 18 days, the radial growth of the checks reached about 35 mm.; 

 0.05 per cent, about equal to check; 0.15 per cent, 8 mm.; 0.3 per cent, 1 mm. There 

 was usually no growth on higher concentrations until after about four weeks, and it 

 was comparatively slight even after six to eight weeks, reaching only 1 to 8 mm. The 

 toxic cultures generally were denser and of brighter tan color than the check. 



Fomes pinicola: In two weeks, the radial growth of the check reached 40 mm.; 0.6 

 and 0.7 per cent, 10 mm. After four weeks, 0.6 and 0.7 per cent reached 35 mm. On 

 the lower concentrations the growth was more fluffy than that on the check. 



Sapwood antiseptic. 



[Laboratory sample No. 1611. Cooperator, J. M. Long, Chicago, 111. Formula (by weight, in water solu- 

 tion): NaCl, 2.92 per cent; CaS0 4 , 0.246 per cent; ZnS0 4 +7 H 2 0, 0.246 per cent; CuS0 4 +5 H s O, 8.182 

 per cent; FeSO<+4 H 2 0, 0.0605 per cent.] 





Tests. 



Times 

 killing 

 point 

 veri- 

 fied. 



Concentration of the preservative (per cent). 



Fungus. 



Num- 

 ber. 



Dura- 

 tion. 



16§ 



25 



30 



50 



60 



75 



1 1 ok. 





17 



Weeks. 

 4 to 5 





4 



4 



3 



2 



2 



1 



i 







Fomes annosus: In about three weeks the radial growth of check reached 40 nun.: 

 50 per cent, 10 to 15 mm.; 75 per cent, very slight growth. Penieillinm developed 

 abundantly on 100 per cent. The preservative up to 25 per cent concentration 

 showed a decided stimulating effect. 



The first concentration is based on the solution, as given above, which was prepared 

 and submitted by the cooperator. Above 16| per cent it was necessary to use a more 

 concentrated solution, and a strength six times the original formula was prepared. 



