6o2 SCIENCE PROGRESS. 



case. The closed air had in the tubes of two out of four 

 species suffered considerable alteration. The increase in 

 weight of the seeds is attributed to metabolism. Since 

 the authors tested only four species and made but few 

 experiments with them, whereas Romanes made most 

 careful trial of nine, and several series of experiments, it is 

 more probable that the results of the latter are more accu- 

 rate ; further, they are confirmed by those of Ewart, De 

 Candolle and Jodin, whereas those of van Tieghem stand 

 isolated. 



The action of vapour of ether, chloroform, alcohol and 

 acetic acid on dormant seeds was also tried by van Tieghem 

 and Bonnier. Seeds of five species were suspended in a 

 flask containing the liquids ; after introduction of the seeds, 

 the flask was hermetically sealed. Exposure of four hours 

 reduced the percentage of normally germinating seeds and 

 retarded development ; exposure of four days accentuated 

 the results, while more prolonged action destroyed 

 * vitality '. The integuments were shown to affot'd 

 enormous protection. The former results contradict again 

 those of Romanes. 



De Bary ^ has stated that seeds of Lepidium sativum 

 withstand immersion of a month in absolute ethylic alcohol ; 

 Ewart (9) has confirmed this, but finds that ' vitality ' is 

 lost after exposure of five weeks. Peas [Pisnrn ?) endured 

 immersion of seven to nine weeks without losing the power 

 of revival in all cases ; immersion of nine weeks however 

 annihilated this. Seeds of Cannabis sativa lost the power in 

 one day, those of Liniun usitafissimum and Triticiim 

 {vulgare ?) by five weeks ; those of Ho7'deuni {dislichum ?) 

 by seven weeks. Fifty per cent, alcohol destroyed the 

 ' vitality ' of these seeds in one day ; those of peas 

 {Pisu77i ?) withstood 90 per cent, alcohol better than both 

 preceding percentages. The seeds mentioned above lost 

 ' vitality ' after immersion of one day in aqueous solution 

 of mercuric chloride (percentage not given) ; peas (^Pisu?nf) 

 however withstood it in alcoholic solution from three to six 

 weeks. 



^ Lecinres on Bacteria, p. 63. Quoted by Ewart. 



