[61] Hellenbach, in his book, Magie der Zahlen, says regarding the number seven.
"The law governing the phenomena on which our knowledge is based decrees that the vibrations of sound and light regularly increase in number, that they are grouped in seven columns, and that the vibratory elements of each column have so close a relation to one another that not only can it be expressed in figures, but it is even confirmed by practice in music and chemistry.
"The fact that this variation and periodicity are governed by the number seven cannot be disputed; it is not a matter of chance: there is a cause and we ought to discover it."
In his table of the elements grouped according to atomic weight, Mendelejef also acknowledges that the number seven controls what he calls the Law of periodical function. He reaches conclusions similar to those of Hellenbach.
Dr. Laycock, in his Articles on the Periodicity of Vital Phenomena (Lancet) 1842, sums up as follows:—
"It is, I think, impossible to come to any less general conclusion than this, that, in animals, changes occur every 3-1/2, 7, 14, 21 or 28 days, or at some definite period of weeks."
[62] See Man and his Bodies, by A. Besant.
[63] The size of the causal body varies according to its development. It has been named causal, because it contains within itself the causes or germs of all the other bodies, with the exception of the denser part of the physical. We say denser because the physical body is double: its etheric part belongs to the causal body, its visible part comes from the parents.
[64] The mental body, which is, as it were, an ephemeral flower of the causal, is born and developed in each incarnation, disintegrating after the devachanic (heavenly) life.
[65] It moves more or less freely on the astral plane, according to the development of the astral body. In men of low development, this body cannot be separated from the physical, under penalty of a nightmare which brings about a waking condition.