There are some abnormal cases, however, in which other parts of the etheric body respond to these additional vibrations as readily as, or even more readily than, the eye. Such vagaries are explicable in various ways, but principally as effects of some partial astral development, for it will be found that the sensitive parts of the body almost invariably correspond with one or other of the _chakrams_, or centres of vitality in the astral body. And though, if astral consciousness be not yet developed, these centres may not be available on their own plane, they are still strong enough to stimulate into keener activity the etheric matter which they inter-penetrate. When we come to deal with the astral senses themselves the methods of working are very different. The astral body has no specialized sense-organs--a fact which perhaps needs some explanation, since many students who are trying to comprehend its physiology seem to find it difficult to reconcile with the statements that have been made as to the perfect inter-penetration of the physical body by astral matter, the exact correspondence between the two vehicles, and the fact that every physical object has necessarily its astral counterpart. Now all these statements are true, and yet it is quite possible for people who do not normally see astrally to misunderstand them. Every order of physical matter has its corresponding order of astral matter in constant association with it--not to be separated from it except by a very considerable exertion of occult force, and even then only to be held apart from it as long as force is being definitely exerted to that end. But for all that the relation of the astral particles one to another is far looser than is the case with their physical correspondences. In a bar of iron, for example, we have a mass of physical molecules in the solid condition--that is to say, capable of comparatively little change in their relative positions, though each vibrating with immense rapidity in its own sphere. The astral counterpart of this consists of what we often call solid astral matter--that is, matter of the lowest and densest sub-plane of the astral; but nevertheless its particles are constantly and rapidly changing their relative position, moving among one another as easily as those of a liquid on the physical plane might do. So that there is no permanent association between any one physical particle and that amount of astral matter which happens at any given moment to be acting as its counterpart.