33 
internal layers will be seen to withdraw themselves from the ex- 
ternal, in the form first of a wrinkled membrane ; and this, gra- 
dually contracting towards the centre, the granule will finally 
appear as a spherical smooth-walled vesicle, with fluid con- 
tents, and with an irregular nucleus-like body—the altered 
internal layers—lying upon some part of the inner surface of 
its walls. 
The author believes, with Schleiden, that the so-called 
‘*nucleus” of Fritsche is a minute cavity in the unaltered gra- 
nule, becoming greatly enlarged by the action of a high heat, 
as in roasting. ‘The contents of this cavity are rendered blue 
by iodine, and assume a granular appearance under the action 
of acetic acid; they are probably fluid or amorphous amylum. 
From the appearance frequently presented by the granule 
under the operation of certain re-agents, and especially during 
the commencing action of hot water, it would seem to follow 
that there are definite lines of cleavage in the granule at right 
angles with the concentric lamelle. 
In conclusion, the author maintained, that the structure 
of the starch granule, as advocated in the present paper, was 
much more in accordance with the centripetal than with the 
centrifugal theory of its growth; but that, while it is to be 
viewed as really a laminated vesicle, it cannot be properly 
included in the category of the true organic cell. 
Dr. Neligan objected, that if the internal and external 
coats of the potato starch granule be different in constitution, 
the chemical test commonly applied to distinguish the differ- 
ent kinds of starch would be inapplicable. Wheaten starch, 
when triturated slightly, is not as readily coloured by iodine 
as the starch produced from potatoes, and this seemed to him 
to be inconsistent with Dr. Allman’s theory. 
Mr. L. Moore made some observations in reference to the 
experiments and observations made by Dr. Allman and others 
who have studied the structure of the starch granule. 
VOL. VI. D 
