510 
slightest alteration in the conditions of life will cause 
extinction. ’ 
If selection tends to diminish the variability of a species, then 
it clearly follows that as selection has been by hypothesis the 
most important means of modifying organisms, variation must 
have been much greater in past times than it is now. In fact, 
it must have been progressively greater the farther we go back 
from the present time. 
The argument which I have just laid before you points, if carried 
to its logical conclusion—and I see no reason why it should not 
be so carried—to the view that at the first origin of life upon 
the earth the variability of living matter consequent upon the 
act of conjugation must have been of enormous range : in other 
words, it points to the view that heredity was a much less im- 
portant phenomenon than it is at present. Following out the 
same train of thought, we are inevitably driven to the conclusion 
that one of the most important results of the evolutionary 
change has been the gradual increase and perfection of heredity 
as a function of organisms anda gradual elimination of vari- 
ability. 
This view, if it can be established, is of the utmost import- 
ance to our theoretical conception of evolution. because it 
enables us to bring our requirements as to time within the limits 
granted by the physicists. If variation was markedly greater 
in the early periods of the existence of living matter, it is clear 
that it would have been possible for evolutionary change to have 
been effected much more rapidly than at present—especially 
when we remember that the world was then comparatively un- 
occupied by organisms, and that with the change of conditions 
consequent on the cooling and differentiation of the earth’s sur- 
face, new places suitable for organic life were continually being 
formed. It will be observed that the conclusion we have now 
reached, viz. that variation was much greater near the dawn 
of life than it is now, and heredity a correspondingly less im- 
portant phenomenon, is a deduction from the selection theory. 
It becomes, therefore, of some interest to inquire whether a 
suggestion obtained by a perfectly legitimate mode of reasoning 
receives any independent confirmation from other sources. The 
first source of facts to which we turn for such confirmation must 
obviously be paleontology. But paleontology unfortunately 
affords us no help. The facts of this science are too meagre to 
be of any use. Indeed, they are wanting altogether for the 
period which most immediately concerns us—namely, the period 
when the existing forms of life were established. This took 
place in the prefossiliferous period, for in the earliest fossil- 
iferous rocks examples of almost all existing groups of animals 
are met with. 
But although paleontology affords us no assistance, there is one 
class of facts which, when closely scrutinised, do lend some 
countenance to the view that when evolutionary change was at 
its greatest activity, ze. when the existing forms of life were 
being established, variation was considerably greater than it is 
at the present day. 
But as this address has already exceeded all reasonable limits, 
and as the question which we are now ‘approaching is one of 
very great complexity and difficulty, I am reluctantly compelled 
to defer the full consideration and treatment of it to another 
occasion. Ican only hope that the far-reaching importance of 
my subject and the interest of it may to some extent atone for 
the great length which this address has attained. 
APPENDIX. 
The following observations on the condition of the male re- 
productive organs in highly variable plants are quoted from 
Darwin’s ‘Variation of Animals and Plants under Domes- 
tication,” vol. ii. p. 256 e¢ seg. 
In certain plant hybrids which are highly variable, it is known 
that the anthers contain many irregular pollen-grains. Exactly 
the same fact has been noticed by Max Wichura in many of our 
highly cultivated plants which are extremely variable, and 
which there is no reason to believe have been hybridised, such 
as the hyacinth, tulip, snapdragon, potato, cauliflower, &c. 
1 The expression extinction of species seems to be used in two senses 
which are generally confused. Firstly, a species may become modified so 
that the form with which we are familiar gradually gives place to one or 
more forms which have been gradually produced by its modification. That 
is to say, a character orseries of characters becomes gradually modified or 
lost in successive generations. This is not really extinction, but develop- 
ment. Secondly, a speeies may gradually lose its variability, and become 
fixed in character. If the conditions then change, it is unable to adapt itself 
to them, and becomes truly extinct. In this case it leaves no descendants. 
We have to do with death, and not with development. 
NO. 1560, VOL. 60] 
NATURE 
[SEPTEMBER 21, 1899 
The same observer also ‘‘finds in certain wild forms the 
same coincidence between the state of the pollen and a high 
degree of variability, as in many species of Rebus ; but in 2. 
caestus and ¢daeus, which are not highly variable species, the 
pollen is sound.” A little further on Darwin says ‘‘ these facts 
indicate that there is some relation between the state of the 
reproductive organs and a tendency to variability ; but we must 
not conclude that the relation is strict.’” Finally he sums up 
the matter in these words: ‘‘ On the whole it is probable that 
any cause affecting the organs of reproduction would likewise 
affect their product—that is, the offspring thus generated.” 
NOTES. 
In his address to the French Association, 
Boulogne meeting, Dr. P. Brouardel took as his theme 
‘“ Hygiene and its Progress during the last 100 Years.” He 
paid special homage to the memory of the great Englishman 
and Frenchman, Jenner and Pasteur, who had done so much 
for the promotion of medical science. The first operation in 
vaccination made in France was performed at Boulogne, June 
18, 1800. A public monument—a statue of Jenner—records 
the event. Referring to some preventive diseases, Dr. 
Brouardel remarked that in the French army the mortality from 
typhoid fever is now about 12 in 10,000, and in the present 
state of the water supply of many towns it is believed that this 
mortality will not be much reduced. In the German army, 
however, the mortality from typhoid fever is as lowas 1 and 
2 per 10,000, owing doubtless to the fact that an order of 
a Government authority addressed to any municipal body is 
immediately carried out, so that an impure water supply has 
soon to be replaced by a better one. But though some French 
municipalities are indifferent to their responsibilities, others do 
their duty well, and the mortality from typhoid fever for the 
whole of France is only 3 per 10,000. Dr. Brouardel referred 
to several other subjects which came within the range of pre- 
ventive medicine. 
at the recent 
THE application of the Jenner Institute of Preventive Medi- 
cine for permission to alter the memorandum of association so 
as to enable the institute to avail itself of Lord Iveagh’s gift of 
250,000/7, was granted by Mr. Justice Cozens Hardy on 
September 13. 
AFTER four months’ work on his yacht, Dr. H. C. Sorby, 
F.R.S., has returned to Sheffield with many hundred specimens 
of marine animals, preserved by his new methods, so as to show 
lifelike character and natural colour. 
THE Director of the Marine Observatory of San Fernando 
announces that the Spanish Minister of Finance has given in- 
structions that all instruments intended for observations of the 
eclipse of the sun on May 27, 1900, are to be admitted free of 
duty. 
Sirk WILLIAM PREECE, K.C.B., has recently been making 
experiments with an electromagnetic system of wireless tele- 
graphy in the Menai Straits. Using a telephone asa receiver, 
he has succeeded in establishing communication between stations 
half a mile apart, the messages heard being signals on the 
Morse code. 
WE learn from the Scéentzfic American that Prof. J. B. 
Hatcher, of Princeton University, has just returned from his 
geological expedition to Patagonia. The primary object of 
Prof. Hatcher's expedition was to make the most extensive 
collections possible of fossils of Patagonia. He also devoted 
considerable attention to gathering ethnological, botanical and 
zoological specimens. The first Mesozoic mammals ever dis- 
covered were found in Patagonia on this expedition, and 
upward of thirty cases of Mesozoic vertebrates were shipped 
