406 Prof. Hillhouse, On the Swelling of Starch Grains. [May 28, 



in its growth ; while if such halts were but slight the grain would 

 have a more uniform character, and its solution would likewise be 

 more uniform. 



It is perhaps of interest here to note, as it has a bearing on the 

 conclusions from this investigation, though none on the investiga- 

 tion itself, that some old " tous-les-mois " starch {Ganna indica) 

 which I placed in absolute alcohol nearly 5 years ago, the alcohol 

 being since once or twice changed, has not even yet lost its appear- 

 ance of stratification, by loss of water. The doubts early induced 

 by this were of course at the time rank heresy, though to my own 

 mind they were fully substantiated by observations made (at Kew) 

 about two years later, on the formation of compound starch grains 

 in the "reservoir cells" of the cortical parenchyma of various 

 species of Rhipsalis. 



Explanation of ifie Figures. 



(All Figures x about 600.) 



Fig. 1 and 1*. Solution of the starch grain by successive zones, 

 each with rupture of the outer " limiting membrane." Fig. 1 after 

 1 hour's action of Chlorzinc Iodine. Between this and Fig. 1* an 

 interval of 40 minutes continuoiis observation. Slight lamination of 

 the fovilla shewn. 



Fig. 2. Another case. Between (1) and (2) was an interval of 

 10 minutes; between (2) and (3) of 25 minutes. In (3) the air has 

 disappeared from the irregular cleft in the grain; and an extremely 

 thin new zone of swelling is shewn. 



Fig. 3. Grain shewing solid remnant after 48 hours in Chlorzinc 

 Iodine. Outer fovilla shows signs of lamination. 



Fig. 4 — 7. Progress of solution of a grain, and formation of lami- 

 nated fovilla, drawn at intervals of about 5 minutes. 



Fig. 8. Laminated fovilla, resulting from the solution of an isolated 

 grain ; drawn after 24 hours in Chlorzinc Iodine. The depth of 

 shading indicates depth of coloration. 



Fig. 9 — 10. Fragments of laminae separated by pressure. 



Fig. 11 — 13. Laminated fovilla, resulting from the swelling of 

 single grains, and subjected to pressure, after 48 hours in Chlorzinc 

 Iodine. 



