268 
The Queensland Naturalist. 
V"OL. I 
The problem of Heredity is necessarily bound up in the 
problems which the science of embryology is doing so much 
to solve. The more advance was made in the knowledge 
of the structure of the cell, its nucleus, and its functions, 
the processes of cell divisions during the ripening of the eggs 
and sperms, the more prominent became their influence on 
discussions on Heredity. Galton, as a result of observation, 
was the first to have a nearer insight when he propounded 
his theory of the stirp. This he imagined to be a something 
preserved from each germ* cell, and passed on in proportion 
to succeeding generations, providing this for a continuity. 
He made many careful observations and measurements, and 
formulated an exact law. According to this law, each parent 
contributes together one-half of each inherited facult\-, 
J each. The four grand- parents (each 1/16), the great- 
grandparents - 1/16— (1/32 each), etc.; the total amounting 
to 1. You will notice that each term is equal to all following 
numbers. Always understood that averages only are dealt 
with. Prepotencies in some ancestors have little chance of 
asserting themselves, and everything would tend towards 
the average. 
This law of ancestral heredity has been expanded by 
the study of Biometry into attempts to improve the human 
race under the name of Eugenics, and much valuable work 
is done, especially by Prof. Karl Pearson. 
The most searching and practical work on Heredity 
has been done probably by Y'eismann. Y’hen he enquired 
for actual proofs of transmission of acquired characters, he 
was not able to find a really satisfactory one. He, therefore, 
studied the process of fertilisation and growths of the embryo, 
with a view of either proving or disproving it. His researches 
ed him to formulate his theory of the germ plasm. 
He first distinguished between two kinds of substance 
in cells, germ-plasm, and somatoplasm. This last is the 
ordinary substance of which body cells may be said to be 
composed of, but has no reproductive powers. The germ- 
plasm is restricted to germ cells only, which also contain 
somatoplasm. These, therefore, possess the potentiality of 
building up the body anew, and also provide a continuation 
of the species through continuous germ- cells, and inheritance 
depends on the continuance of the germ-cells. He elaborated 
his theory from time to time. He said later (1892) : “ This 
substance can never be formed anew ; it can only grow, 
multiply, and be transmitted from one generation to another.'* 
My theory, therefore, may well be termed Blast ogenesis,'" 
or origin from the germ plasm, in contradistinction to 
** Pangenesis,*' or origin from all parts of the body, which 
was Darwin's idea. Germ-cells alone transmit the reproduc- 
tive substance or germ-plasm in uninterrupted succession 
