196 
MICROSCOPIC OBSERVATION. 
By Tuomas TAYLOR, MICROSCOPIST. 
CELLULOSE AND STARCH IN PLANTS AND ANIMALS. (Continued from 
the July Report for 1875.)—As cellulose and starch have very important 
relations to man and the lower animals as food-constituents and in other 
respects, I have deemed it advisable to continue my investigations on 
these substances. 
1. Fig. 1 represents a fiber of cotton in its natural condition; 2, a 
fiber subjected to the action of strong sulphuric acid; 3, a fiber on which 
was first placed a drop of a strong amber-colored solution of tincture of 
iedine, followed by a drop of commercial muriatic acid, and immediately 
afterward by a drop of concentrated sulphuric acid. In consequence 
of the combinations of the sulphuric acid with the water of the muri- 
atic, the liquid boils two or three ‘seconds, and by this chemical action 
the cellulose or cotton-fibers are quickly changed in their structure and 
chemical composition. When viewed under a power of about 100 diame- 
ters, the fibers will be found to have been reduced to a starchy condi- 
tion, and in many cases will appear in the form of disks or beads of — 
a well-defined blue color; 4 represents a fiber of flax in its natural 
condition; 5, when treated with concentrated sulphuric-acid; 6 and 7, 
when acted on by the tincture of iodine and acids, as described in 
the case of cotton-fibers. Membraneous cellulose and also amor- 
phous may be stained blue in the same manner, but they retain their 
original forms. To illustrate this, saturate a few grains of bleached 
Aax in commercial muriatic acid, then add, by degrees, concentrated 
sulphuric acid, and stir the mixture with a glass rod until the mass 
Becomes pulpy or partially dissolved; then add to it an excess of 
water and let it stand for several hours to allow the cellulose to precipi- 
tate, after which decant off the clear water. This process of adding 
water or washing must be repeated several times, or until the solution 
has no acid taste, when the pulp will be ready for future experiment. 
If a portion of the pulp be viewed by a power of about 100 diameters, 
it will be seen to consist mostly of amylaceous precipitated matter, 
(amorphous,) void of organic structure, combined with partially-dissolved 
flax fibers. If it be ground with a glass spatula and viewed again it 
will be seen that the only change effected is the reduction of the size of 
the particles of flax, no starch-like bodies being observable ; but if there 
new be added to it one drop of the tincture of iodine, one of muriatic 
and one of suphuric acid, blue globular and starch-like bodies will be 
formed from the undissolved flax. That portion of the flax-fiber which 
was rendered soluble in the acids and precipitated on the addition of pure 
water, is amorphous cellulose, and remains structureless. If the pulp 
so treated be ground again with a spatula while combined with these 
solvent acids, a much. greater variety of these globular bodies will 
appear. Rotation and a solvent solution are all that is necessary in 
this case to produce these artificial starch-like granules in abundance. 
Zt will be observed that these amylaceous granules.are formed from two 
distinct causes. The first mentioned results from the expansion of the 
disks described, and the second from the action of the soluble acids, 
assisted by the rotation of the partially-dissolved flax particles. 
The spiral cellulose vessels of the ovaries of the blossoms of fruit 
and tender leaves of the beech are stained purple and sometimes pale 
