JjOvgHvliy of 8<'e<l-<. 409 



shown still fuveriiii;- the seed, and the thickness of it l)e the 

 same as that of the original cuticle, it would be safe to con- 

 clude that in the coverings of hard seeds at least an insoluble 

 basis is present throughout. 



Tbe method used Avas as follows — the seeds were treated for 

 varying lengths of time with chloroform, warm alcohol, tur- 

 pentine, and strong caustic i>otash, sections were made of the 

 seeds which swelled in water after the treatment, these were 

 stained as before with chor-zinc-iodine and compared with 

 similar preparations of untreated seeds. The seeds used were 

 the same as those selected for the examination of the structure of 

 the seed coat. Of the reagents used chloroform and caustic 

 potash gave most satisfactory results, and turpentine had no 

 effect whatever. Boiling absolute alcohol produced swelling 

 in all cases, but as soaking in water or 70 per cent, methylated 

 spirit at a corresponding temperature gave similar results it 

 seems probable that the action is uuiinly a physical one, due 

 to the melting of the fatty substances l)y the action of heat. 



Indujiifera arrertd and Ci/tisus albii'^ U'ave similar results 

 in all cases. Boiling in absolute alcohol for two hours' j^ro- 

 duced swelling, and sections of the swollen seeds showed that 

 the cuticle had entirely disappeared. One hour in boiling 

 alcohol caused a few seeds to swell, and in these also the cuticle 

 was gone, but there was a distinct rather ragged bluish line 

 along the outer nuirgins of the cells. As the sections dried 

 this line seemed to shrink somewhat, although, as it was not 

 very thick in the first place, the change was not remarkable. 

 Maceration in chloroform at .30 deof. C. for ei<?hteen weeks was 

 also instrumental in producing swelling, and the stained sec- 

 tions of these seeds showed a marked contrast with those of 

 untreated seeds. TTie outer membrane no longer appeared dark 

 brown, but was tinged with the violet colour of hemicellulose. 

 (See Plate 81, a, b.) A similar result was obtained by soaking 

 the seeds in a saturated solution of caustic potash at 30 deg. C. 

 for four weeks, or by boiling in the same for 5 min. The sec- 

 tions after this last method were unsatisfactory on account of 

 the excessive softening of all the parts by the action of the 

 potash, whereas prolonged soaking in chloroform appears to 

 remove the cutin without affecting in the least the structure 

 of the carbohydrate basis in which it is embedded. 



