Ignorant as we are of the scope, limitation, and even existence, of certain faculties in animals, we can frequently do little more than conjecture the means whereby they perform many of the functions of life. This ignorance leads us naturally at times to refer these powers to the agency of senses like our own; but, in most instances, probably without any foundation in truth. No creature seems less qualified to commit the depredations which it does, than the garden snail. We grieve to see our fruit mangled and disfigured by these creatures, but cannot readily comprehend by what means they obtain the knowledge that its maturity is approaching—though we find that they must be endued with some faculty capable of accomplishing the purpose; for no sooner does a plum, a fig, a nectarine, or other fruit, begin to ripen on the wall, and long before any sensible odor can be diffused from it, even before an experienced eye can detect the approach to maturity, than those creatures, the slug and the snail, will advance from their asylums, though remotely situate, and proceed by very direct paths to the object. This cannot probably be by the guidance of any known faculty. Eyesight was once considered to be situate on the summit of their horns; but this is now known to be erroneous, and we do not know that they have any vision. The acoustic organ of worms and insects is unknown; and it is not by any means ascertained that these creatures ever hear.[66] If they possess the faculty of smelling, in them it must be a very exquisite sense, beyond any delicacy we can comprehend. Thus, excluding human means of comprehension, which appear inadequate, we more reasonably conclude them to be endowed with intelligences for effecting intentions, of which we have no perception, and which we have no capacity for defining. The contemplative man finds pleasure in viewing the ways and artifices of creatures to accomplish a purpose, though he knows not the directing means; and it fortifies the convictions of the believer, by giving him fresh evidences of the universal superintendence of his Maker, that even the slug and the snail, which are arranged so low in the scale of creation, are yet, equally with all, the object of his benevolence and care.