48 
MR. YOUATTS LECTURES 
was, however, no enlargement of any part of the alimentary 
canal, no common cavity which bore the slightest resemblance to 
a stomach, but the alimentary canals or tubes were numerous 
almost beyond calculation. 
Plants had the power of reproduction. In the form of seed or 
offset, bud or rootlet, they contained within themselves the germs 
of similar beings. 
To a certain extent they were possessed of instinct, by which 
he meant, actions, or trains of action, independent of reason, 
tending to preserve the individual or perpetuate the species. 
He related, illustrated by plates, the ingenious but ineffectual 
attempts of John Hunter to make the radicle of the plant grow 
upward and the plume downward. 
He spoke of trees loving moisture throwing out their principal 
roots in the direction of that moisture ; and those to whom mois¬ 
ture would be prejudicial, directing the greater part of them from 
the water. 
He described an ash growing on the wall of a ruin. It flourish¬ 
ed to a certain point, then, finding that it could not derive suffici¬ 
ent nutriment for its increasing bulk, it ceased to grow upward ; it 
seemed to be withering, and directed all its energy and nutriment 
to a new root, which shot out from the wall, and took a direction 
towards the ground. As soon as it had reached and penetrated 
the ground, and could extract from it the food that was required, 
it began again to spread its branches and rapidly flourish. 
He described two trees, one sheltered, and casting out its roots 
equally in every direction, or where nutriment could most easily 
be obtained. The other exposed to the wind on one side only, 
and to that side sending its largest and longest roots, to gain firmer 
support against the violence of the blast. 
These and many others appeared to him to be instinctive acts. 
They had nothing to do with reason, but their evident tendency 
was to preserve the individual, or multiply the species. 
Animals had other powers,—sensation, and locomotion. This 
the boundary line. 
Some singular motions in plants—the shrinking of the sensitive 
plant—the closing of the leaf of the catchfly—the travels of the 
strawberry shoot—the more distant peregrinations of the orchis; 
these indicated susceptibility to certain impressions, but were no 
proof of sensation. They demonstrated that contractility which 
is necessary to bfe, but no dissection had demonstrated in the 
most perfect vegetable the organs on which sensation depends. 
No physiologist had attempted to demonstrate the veriest rudi¬ 
ment of nerves or brain. 
