928 
Proceedings of the Boyal Society 
on the shoulders of the male, the latter may exceed in size ; and 
the same may result in instances, like that of the drones, where the 
activities are excessively low. In regard to general features, then, 
such as higher temperature and greater activities in the males, 
and in reference also to secondary sexual characters, it is no longer 
sufficient to explain these teleologically in reference to sexual selec- 
tion ; both essential and secondary peculiarities must he explained 
as the results of preponderant anabolic or katabolic diathesis in the 
two sexes. 
§ 4. Heredity . — Since the theories of heredity will be discussed 
in a future paper by my friend Mr Arthur Thomson, the subject 
shall he referred to here only in briefest outline. To explain the 
likeness of offspring to parent numerous hypotheses, both physiolo- 
gical and physical, have been suggested, which, though perhaps too 
mystical in their present forms, will yet, to some extent at least, 
admit of being re-expressed in the more real and definite terms 
of protoplasmic changes. 
An important line of investigation, first noted by Jager, but 
recently followed up and corroborated by Hussbaum, and especially 
by Weismann, emphasises the fact that, in many cases at least, the 
future reproductive elements are isolated from the germ at an early 
stage in the development, and, in some cases, before the differen- 
tiation of the body-cells. In the direct continuity between the 
rudimentary reproductive organs of the embryo and the parent 
ovum, there is a continuity of protoplasm, which is in itself a 
partial explanation of the continuity in history. 
Now, if the reproductive elements start with a specific proto- 
plasm continuous with that of the combined mother ovum and 
fertilising sperm, that is, with a concentrated accumulation of 
characteristic anastates and katastates, the simple fact that the 
products of protoplasmic change must be fixed, definite, and con- 
tinuous, as in all chemical processes, gives us at once a protoplasmic 
basis from which to explain the constant and necessary symmetry 
of segmentation and development. 
On the other hand, if there be cases where the superficial charac- 
ters acquired by the individual parent are transmitted to the off- 
spring, apart from the result of similar environment and experience, 
it must not be forgotten that all the organs of the body do to a 
