208 TKANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



in 50 p.c. alcohol for 5 days, 7 days, etc. The seeds were 

 then washed, counted and planted in pots. Each pot 

 was divided into two equal halves by a longitudinal par- 

 tition on one side of which the seeds experimented with 

 were planted and on the other a similar number of the 

 same but normal seeds which had been kept in a dry 

 place whilst the experiment was going on. The number 

 of seeds which germinated in each batch was counted and 

 the percentages calculated. In the tables the percentages 

 given are always comparison percentages with normal 

 seeds. Thus after 3 weeks immersion in abs. alcohol 

 46 p.c. of Cress seeds germinated, of normal seeds 90 p.c, 

 the comparison percentage therefore being 51 p.c. 



Cress. 



3 weeks. 



4 weeks. 



5 weeks. 



Abs. Alcohol. 



51 p.c. 

 germinated. 



10 p.c. 



None. 



The effect of 50 p.c. alcohol contrasts very markedly 

 with that of abs. alcohol. Thus Cress seeds planted after 

 5 and 7 days immersion in 50 p.c. alcohol were found to 

 have entirely lost their vitality, none germinating, i.e., 

 the dilution of alcohol with its own bulk of water causes 

 it to exercise a much more deadly influence not only upon 

 Cress seeds, but as will be seen later upon other seeds 

 also. 



The external layer of the integument of a Cress seed 

 swells up in water to form a fairly thick mucilaginous 

 covering over each seed. In doing so it absorbs a large 

 amount of water and this water is forcibly interpolated 

 between the molecules of the mucilaginous layer, separa- 

 ting them more widely and hence increasing the size of 

 the intermolecular interstices. In abs. alcohol no such 

 swelling of the mucilaginous coat takes place and the 



