The answer is simple. Because they have the psychic vehicles, the five cognizing senses, by which to convey the sensation of the external stimulus to the mind, and therefore they need no physical brain or nerve. Only, having no physical openings, they cannot manifest the effect of those sensations outside themselves, as animals do; and only an instrument, like the galvanometer, is able to detect the sensations and indicate them by the deflection of its needle. Mineral and vegetable matter having all the twenty-four principles in them, have the mind and the senses, too. Only, they are in a shut-up, undeveloped state, and perform their undeveloped, crude functions like an unconscious mechanism. It is through the senses that sensations are perceived; and had not the senses been present within a piece of metal or a vegetable, there would be no sensation in it, and therefore the galvanometer would have been useless in its application and results, because, there being no sensation, there would be no deflection of the needle. Professor Bose's experiments conclusively prove not only the unity, but the uniform composition and construction of the whole universe; that all its composing principles are present everywhere; that in some phases they are in a latent and in others in manifest state. The tests of the galvanometer also prove that what is true of the whole universe is true of a particle of earth; that the whole universe is one whole living mass, like a single living being, and that every molecule of its composition is a universe in embryo; because every molecule is instinct with all the forces and properties of the twenty-four principles, which are the materials as well as the attributes of the cosmos. SECTION XVI. PHYSICAL AND ASTRAL BODIES. It is the ignorance of the knowledge of the constitution of the universal and human bodies that forms one of the chief obstacles of a correct study of the laws operating behind external Nature, It is the general belief of modern humanity that the human body is made up of flesh and blood alone. This is true so far as the physical body is concerned. But there is another body within us finer than the physical which is the real body and of which the physical body is the outer encasement. This real body is called the Astral Body. The whole human body is like a clock of which the physical covering is its case and the astral body its works. As the mechanical part of a clock is the real clock and its case with its dial and hands forms its covering by which it indicates its working, so the astral body is the mechanical part of the human body and the physical is its case through which it indicates its operations. Though far from perfect, the analogy is very suggestive. For instance, the mechanical part of the clock cannot serve its purpose without the aid of the case, dial and hands. The astral body likewise cannot be of any use without the co-operation of the physical body.