DIGESTION OF AMYLACEOUS SUBSTANCES. 
419 
amylaceous matters are digested in the stomach by the 
action of the gastric juice, like other aliments. This portion 
we extract entire. 
“ Whether in the crude or hydrated state, fecula is more or less perfectly 
digested in passing through the digestive tube, at least, among warm- 
blooded animals. We can convince ourselves of this fact by examining 
the excrements of different animals fed upon simple or compound feculent 
substances, and seeking in them for the grains of starch remaining intact, 
and capable of assuming a blue colour with iodine. Now the result of this 
examination is, generally, that none are found, or, if any, in such small 
number that they appear to be there accidentally. Whence we must con- 
clude that fecula, eaten even in the raw state, undergoes, during its 
passage through the gastro-intestinal tube, some modification which permits 
of its absoption. Let us see in what this modification consists. 
“ Feculent grains, of whatever description, as I mentioned before, are 
composed of concentric membranes, which themselves are formed of an 
infinite number of granules united by traces of nitrogenous matter. On 
the other hand, I have shown in my ‘ Treatise on Digestion,’ that the 
gastric juice, which is entirely without action on non-nitrogenous principles, 
and consequently on the granules, properly so called, attacks and softens 
most of the nitrogenous principles of organic origin, under the influence of 
a suitable temperature. Accordingly it was only natural to think that, 
when the grains of fecula are subjected, in the stomach, to the action of 
the gastric juice, this fluid attacking the nitrogenous covering which unites 
the granules, these are disaggregated the more rapidly because the peri- 
staltic action of the stomach concurs towards the same aim. Moreover, 
if, as I have said, the property of assuming a blue colour with iodine does 
not belong to the granules themselves, but to a thin covering in which 
they are enveloped, it is evident that these granules would lose the power 
of becoming blue the moment that the above-mentioned envelope has been 
removed or even modified by the gastric juice. This is indicated by the 
theory established a priori ; let us now see wliat direct experiment will 
show us. 
“For this purpose it is sufficient to examine with iodine and a micro- 
scope what happens to the fecula in traversing the different sections of 
the digestive tube. Having therefore fed various animals, fowls, pigeons, 
rabbits, goats, dogs, & c., either with pure fecula and grain in the raw 
state, bread or other analogous substances, I have proved the following 
facts : 
“ The acid matter of the stomach, suitably diluted with water, exhibited, in 
the microscope, one portion of the granules of the fecula, still intact and 
capable of assuming a blue coloration with iodine ; other granules, like- 
wise colorable with iodine, were swelled, deformed, exfoliated as if they 
had been subjected to the action of boiling water. Among these partially 
destroyed grains were seen likewise a great many amylaceous granules, 
precisely similar to those which had been separated in a Papin’s digester, 
with this difference, that, whereas the latter became blue, the granules 
disaggregated by the gastric juice, were simply rendered yellow by 
iodine. 
“ In the upper portion of the small intestine we no longer found entire or 
exfoliated granules assuming a blue colour; but, on the contrary, the 
granules assuming a yellow colour were found by myriads. As we advanced 
toward the large intestines, the number of these granules gradually 
diminished, so that at the end of the digestive tube only a few were found 
which appeared to have escaped absorption. 
