404 Prof. Hillhouse, Some Observations [May 28, 



Method 3 again gives no information distinguishable from 1 but 

 what may be referred to method 4. In this method of swelling (4) 

 we have an additional phenomenon. We have here, also, an outer- 

 most resisting layer which overlies an unresisting layer of some 

 thickness. The latter becomes turgid, overcomes the resistance of 

 the outer layer, ruptures it, the whole is dissolved off, but only to 

 expose to the action of the reagent another resisting layer similar 

 to the first, followed by a similar soft band, yet another resisting 

 layer, and so on. From this it follows, if my deduction be true, 

 that the starch grain is composed of a series of layers each bounded 

 outwardly by what is sometimes a firm " limiting membrane," of 

 some modified organisation, which for some time resists the action 

 of what is, for its subjacent layer, an easy solvent. 



What now do we learn from method 5 ? Here we have clearly 

 another case, showing the " layering " of the grain, but, showing 

 further that, under certain circumstances, each separate layer with 

 its outer limiting membrane can swell, become apparently detached 

 from its subjacent layer, pass outwards in position, but yet main- 

 taining its own continuity. 



This brings up a highly important question to solve, namely to 

 what extent the laminae in the swollen grain are independent of 

 one another, if they are so at all. In order to solve this problem 

 there is only one method open to us — the application of pressure, 

 with the intent to separate one from another these different layers, 

 if they be so separable. Bearing in mind that we have here to do 

 with soft lamina?, exceedingly delicate, and in a semi-glutinous 

 state, and therefore tending to be mutually adherent, and that the 

 only basis we have to work upon is the fact, deduced from 4, that 

 the outer part of each lamina is more resistant than the material 

 within and without it ; bearing this in mind, I should not have been 

 surprised had pressure failed to give any ascertainable results. 

 This was s however, by no means the case. While the great majority 

 of the swollen grains did what was expected of them, that is, 

 flattened, and then went into a disorganised heap, here and there 

 all over the field could be seen delicate fragments of the outer 

 lamina?, often of considerable peripheral extent (Figs. 9 and 10), 

 sometimes flattened out, sometimes folded, but sometimes preserv- 

 ing well-nigh intact the shape they bore while on the grain from 

 which they had been squeezed ; while in other cases the grains 

 themselves could be seen with their envelopes torn, opened out, 

 and separated in every conceivable manner. Examples of this will 

 be seen in Figs. 11, 12, and 13; Fig. 13 representing a case of a 

 peculiarly striking nature. 



These facts, I think, justify us in concluding that the envelopes 

 are anatomically distinct from one another. 



Let us now bring these results to bear upon our interpretation 



