io8 



state in contact wnth water, when endosmotic changes followed, the 

 less dense liquid being absorbed. After the absorption the grains were 

 found to have burst in the direction of their axes, the rupture indicating 

 a membrane that had been corrugated by release from unusual tension? 

 whilst the covering of the I'emaining portion of the granule was 

 visible, in distinct longitudinal wrinkles, from the hihim downwards. 

 He submitted that were the corpuscle composed of superposed laminae 

 only, the addition of water in the manner described ought not to 

 rupture it, or if this happened, the fracture would be in the direction 

 of the laminar surfaces and not at right angles to them or their 

 supposed order, as happened in his experiments. He further held that 

 the bands or lines observed in starch grains were mere plications of 

 the outer membrane, because they entirely disappeared on swelling 

 the corpuscles with any liquid. 



Others again considered that the nucleus was a point either solid 

 or hollow, from which growth proceeded, and that the lines represented 

 successive deposit on the exterior varying in density, there being no 

 investing membrane at all. We were accustomed to say that while 

 the cold water had no action on starch boiling water would break up 

 its granules and dissolve them, but this seemed to be very doubtful ; 

 for if one part of starch were boiled with loo parts of water, the white 

 colour of the corpuscles would disappear and the whole present a 

 perfect solution, which would traverse a compact filter. Payen 

 immersed the bulb of a hyacinth in such a filtered solution, and 

 succeeded in separating the apparently-dissolved starch ; for there 

 appeared, as the rootlets absorbed the water, particles of starch 

 adhering to them, which were turned blue by iodine, whilst a section 

 of the roots of the bulb gave no indication with this test of the presence 

 of amylaceous matters. Hence it was evident that the fine capillaries 

 of the plant, being too small to permit the passage of the particles of 

 starch, caused their accumulation on the surface. 



Starch was also separated from its apparent solution by freezing 

 and thawing several times, when it was precipitated in flakes, and 

 could be made into a felt-like substance, which was used in the manu- 

 facture of certain kinds of cartridges and for other purposes, as a 

 substitute for paper. It would appear that boiling water did not 

 dissolve starch granules, but increased their size to an enormous 

 extent and rendered them transparent. He had seen it stated that 



