204 University of California Puhlications in Botany [Vol. 5 



in this connection. In general the suggestions given by Love 

 and Leighty (1912) have been followed in modified form. The 

 action of concentrated sulfuric acid (sp. gr. 1.84) for lengths of 

 time as short as one minute in the case of 53/03 ate the seed 

 coats entirely away and destroyed any possibilities of germina- 

 tion. This was proved by a number of tests and by microscopical 

 examination. It is, however, entirely conceivable that the seed 

 of other strains of tobacco, better protected as to seed coats, will 

 give more favorable results with the concentrated acid — i.e., seed 

 of IT. C. B. G. 150/07 possibly. A considerable number of 

 experiments showed that treatment -s^ith 50 per cent, 70 per cent, 

 and 80 per cent sulfuric acid gave the best results, and the 

 majority of the tests were made after treatment with 80 per cent 

 acid for varying lengths of time. 



A small quantity of the seed to be tested was placed in a 

 small vial and covered with the 80 per cent acid at room tem- 

 perature. After allowing the acid to act for the desired length 

 of time the vial was at once filled with tap water and the seed 

 and greatly diluted acid poured through strong cloth which 

 served to retain the small seeds. The seeds were washed for one 

 or two minutes on the cloth with a fine stream of tap water 

 and then transferred to another cloth-covered vial in which 

 they were further washed with running water. The eifects of 

 prolonged washing after sulfuric acid treatment will be further 

 discussed below. After the washing the seed was counted out in 

 two lots of one hundred each, as above noted, on to the blotting 

 paper holders and placed in the germinating case in the green- 

 house. 



IV. RESULTS WITH SULFURIC ACID TREAT:\IEXT 



The following table expresses the effect of sulfuric acid 

 treatment — 50 per cent, 70 per cent, and 80 per cent acid — upon 

 the germination of the seed of 78/09 produced in 1911. Because 

 of the small amount of seed available duplicate tests were not 

 possible and only fifty seeds were used in each individual test. 

 After the treatment with acid the seeds were washed with 

 running water for an hour while in the control the seeds were 

 placed dry on the filter paper. 



