114 



THE BOTANICAL MAGAZINE. 



[Vol. XXXIV. No. 403. 



Thermal death point. One cubic centimeter of bacterial suspen- 

 sion, which was prepared dissolving one loopful bacterial mass of 3 

 days old glucose agar culture by 32°C in 5 c.c. of sterilized physiologi- 

 cal water, was taken in small test tube, 1 cm. in diameter and 0,5 

 mm. thick walled, and exposed in hot water of certain temperature. 

 After exposure of certain minutes one loopful of the suspension was 

 transferred to the glucose bouillon. The results of experiments are 

 suramerized in the table below : 



Minutes 



Temp. 



50°c 



53*c 



55°c 



10 



20 



Sensitiveness to sunlight. Thinly sown glucose agar plates of B. 

 millet iae were exposed bottom up to sunlight protecting one-half of 

 each plates from the light by tinfoil. The results are as follows. 



Ex. I. A.M.II 4':-II 34', 30, Nov. 1918. 



Minutes 



exposed 



Number of 

 dishes 



Temp, rising in the 

 medium 



Number of colonies 

 appearing on both parts 



5 



10 

 15 

 30 



12-17,5°c 



12-18°c 

 12-19,2°c 



12-20,2°c 



no effect 



Ex. II. A.M. 



II 40' PM. 



12 40', 10, Dec. 1918. 





Minutes 



Number ol 





Temp, rising in the 



Number of colonies 



exposed 



dishes 





media. 



appearing on both parts. 





1 







oo /go 



15 



2 





•10.8— 23.9 °c 



32/30 





3 



1 







28/27 

 30/80 



30 



2 

 3 

 1 





10.8— 24,2 a -c 



33/92 



40/54 



5/56 



60 



2 





10.8— 21.2°c 



2/112 





3 







5/80 



