ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
381 
tendency in a race to progress in a definite direction, unless equilibrium 
be maintained by any other equipollent factor, exhibited in the form of 
a differential death-rate on the most fertile. Such a differential death- 
rate probably exists in wild life, at any rate until the environment 
changes and the equilibrium between natural and reproductive selection 
is upset. How far it exists in civilised communities of mankind is 
another and more difficult problem, which Mr. Pearson has partially 
dealt with in one of the essays in his ‘ Chances of Death.’ 
In the memoir of which an abstract is published, Prof. Pearson (with 
the assistance of Miss Alice Lee and Mr. Leslie Bramley-Moore) deduces 
the following conclusions : — 
(1) Fecundity in the brood-mare is inherited from dam to mare. 
(2) It is also inherited from grand-dam to mare through the dam. 
(3) The latent quality, fecundity in the brood-mare, is inherited 
through the sire ; this is shown not only by the correlation between 
half-sisters, but by actual determination of the correlation between the 
latent character in the sire and the patent character in the daughter. 
(4) The latent quality, fecundity in the brood-mare, is inherited by 
the stallion from his sire ; this is shown not only by the fecundity- 
correlation between a sire’s daughters and his half-sisters, but also by a 
direct determination of the correlation between the latent quality in the 
stallion and in his sire. 
The authors are led to the conclusion that fertility is inherited in 
man and fecundity in the horse, and therefore probably that both these 
characters are inherited in all types of life. It would indeed be difficult 
to explain by evolution the great variety of values these characters take 
in allied species if this were not true. That they are inherited accord- 
ing to the Galtonian rule (of ancestral inheritance) seems probable, 
though not demonstrated to a certainty. 
Regeneration.* — Prof. August Weismann, in his recent essay on this 
subject, reviews certain recent regeneration experiments, and discusses 
their bearing on his previously expressed views on the subject. According 
to these views, regeneration is not an immediate and necessary expression 
of the nature of the organism, but is an adaptive phenomenon, present 
wherever an organ of great biological importance is liable to loss or 
injury in the ordinary course of life. This position obviously demands 
two sets of proofs. It must be known, firstly, that all parts capable of 
regeneration are liable to be lost under ordinary conditions, and secondly, 
that organs not so liable are not regenerated. Among the latter Prof. 
Weismann includes internal organs which are not renewed after injury. 
Among organs which are renewed, but which have not hitherto been 
shown to be naturally liable to injury, are the jaws of the stork (renewed 
after accidental injury) and the lens of the eye in newts. But it has 
been recently shown by Bordage that the beaks of cocks are frequently 
injured during cock-fighting, and are then renewed. This suggests the 
possibility that the same accident may occur in the stork, where the 
males are also great fighters. In the case of newts, Prof. Weismann 
finds that the head, and possibly the eye, are often injured by the larvae 
of Dytiscus marginalis. 
* Anat. Anzeig., xv. (1899) pp. 445-74 ; and in Nat. Sci., xiv. (1899) pp. 305-28. 
