
— May 11, 1871} 
NATURE 
25 


server whose researches may have been omitted, to attri- 
bute the neglect to the disturbing influence of recent 
events. The earth and her satellite are treated at some 
length, and the questions of the moon’s influence on 
the earth’s atmosphere, the winds, weather, and magnets, 
are fully discussed. The chapter on meteorites is 
very interesting. We are told, on the authority of Miller 
and Haidinger, that the earliest mention of meteorites is 
probably in Iliad xv. 18—22, where the anvils spoken of 
by Jupiter are supposed to refer to these phenomena. Livy 
mentions a shower which some think may have been a 
star shower ; and the famous black stone in the Kaaba, 
at Mecca, is said to be undoubtedly a meteorite of great 
antiquity. Numerous analyses of meteorites are given, 
and tables are added containing full details of all those 
which are recorded to have fallen from the earliest times. 
There are similar tables with regard to comets and star- 
showers ; and finally we have two well-executed plates of 
the appearance of different sun-spots, and a chart of part 
of the moon’s surface. Weshould like to see an English 
edition. 
The Theoretical Astronomy of Dr. Klinkerfues, director 
of the Royal Observatory of Géttingen, is a reproduction 
of lectures delivered by him in that University. This is 
the first part of the work, and its object is to give an ex- 
planation of the means by which the courses and posi- 
tions of heavenly bodies are determined. It is not 
adapted to the general reader, but will prove a useful 
companion to the mathematician who wishes to obtain an 
insight into astronomical methods of calculation. Several 
very good figures accompany the text. 
Gar. A. 
Kuklos ; an Experimental Investigation tnto the Relation- 
ship of Certain Lines. By John Harris Part I. (Mon- 
treal, 1870) 
IN a review of Prof. Bretschneider’s History of Early 
Geometry we have mentioned some clever attempts to 
square a circle, made at a time whea this problem en- 
gaged the attention of the first mathematicians. Then, 
however, as at present, there existed circle squarers of a 
different kind, who excel only in demonstrating their own 
ignorance. A fine specimen is preserved by Simplikios. 
Some persons had heard of square numbers which are at 
the same time cyclical, that is to say, the last figure in the 
square number is the same as that of the root, as 25 and 
5. Nothing, of course, could be more evident to them 
than that a number which is both square and cyclos must 
be a measure for the circle. Mr. Harris ranks almost as 
high, only he does not give his conclusions in quite so 
short a form. His book is to consist of four parts in 
quarto, of which the first contains merely a preface, pre- 
liminary arguments, and on the last page an introduction. 
In the preface the author excuses the haste in which the 
publication has taken place, with the remark that if his 
researches are of value they cannot be brought early 
enough before the public,—ifa failure “ the communication 
itself would not be worth the additional labour bestowed 
on improving its form.” This latter conclusion we 
willingly grant. It is only to be regretted that Mr. Harris 
has not had the same opinion of the time he spent in 
writing this communication and preparing the numerous 
and long figures which fill ten large plates. 


LETTERS TO THE EDITOR 
[The Eaiter does not hold himself responsible for opinions expressed 
by his Correspondents. No notice is taken of anonymous 
communications. | 
Pangenesis 
Mr. GALTON—by acting upon the conclusion that the supposed 
gemmules supposed to be detached from the cells of the body at 
different periods of life in the case of the higher animals swarmed 


in the blood prior to their supposed collection and union to form 
the reproductive element—favoured the provisional hypothesis of 
Pangenesis, for he indicated a not improbable manner in which 
the very improbable phenomena involved in the hypothesis might 
actually occur. 
But Mr, Darwin, in NATURE for April 27th, writes to explain 
that he maintains that the gemmules must be ‘‘ thoroughly dif- 
fused”—I conclude, suspended in the fluids which circulate 
freely in every part of the very substance of all the tissues of the 
body. The supposed gemmules must be much more minute than 
the smallest particles that can be seen by the highest magnifying 
powers used in these days, and must be invisible to the eye when 
made to appear five thousand times larger than their real size. They 
must be capable of diffusivn, and, as is suggested by Mr, Darwin, 
much as chemical substances are diffused.* But the terms of the 
hypothesis would imply that the gemmules are actual particles 
suspended and not dissolved in the fluids. 
It is not very encouraging to those who work, to discover after 
having performed numerous and well-devised series of difficult, 
laborious, and troublesome experiments honestly to test the value 
of a hypothesis, that they have been investigating a shadow, and 
to be then informed that the results they have obtained have little 
or no bearing on the question at issue. The ‘‘experiments are 
extremely curious,” says Mr. Darwin, and the experimenter 
“deserves the highest credit for his ingenuity and perseverance.” 
It would, of course, be possible to remove from one animal 
portions of tissue which, according to the hypothesis, sus¢ 
contain the supposed gemmules, if they exist, and graft the 
pieces of tissue upon another, If the experiment was successful, 
and the offspring exhibited any of the characters of the variety 
from which the graft was taken, the opponents of Pangenesis 
would admit the doctrine at once, but if the results were again 
of a negative kind, would Mr. Darwin consider that his hypo- 
thesis had ‘‘received its death blow?” It would certainly beas 
easy to defend it as itis at this time. Nor do I believe it pos- 
sible to obtain a series of experimental results which would lead 
the supporters of Pangenesis to abandon the hypothesis. A firm 
belief in hypothetical gemmules, which cannot be*rendered evi- 
dent to the senses, is not likely to be shaken. 
Depend upon it, neither the well-devised experiments of Mr. 
Galton, nor any other experiments that may be devised, will over- 
throw this doctrine. The provisional hypothesis of pangenesis 
is perfectly safe, and will withstand every attack that may be 
made. It cannot be successfully assailed. Like many favoured 
hypotheses of these days, it can neither be proved to be true 
nor positively shown to be false, and it is open to anyone to 
ground his belief in the truth of this and other doctrines upon the 
fact that they have not been and cannot be disproved. For 
undoubtedly gemmules ay be formed in the manner supposed ; 
if formed, they may be detached ; if detached, they may pass 
through the tissues ; they ay then collect together, and ay form 
reproductive elements. Each one of the countless millions of 
sperm elements produced in such profusion during so many years 
of life ay, indeed, be formed by the union of millions of gem- 
mules which, after meandering through the various textures of 
the body, marshal themselves in order in one particular locality, 
From the vast company thus supposed to have collected, we may 
conceive, by the light of imagination, the formation of regiments 
composed of multitudes of individual gemmules of the same kind; 
and further, it is not difficult to imagine that each individual 
gemmule of every regiment may move away and unite with thou- 
sands and tens of thousands of others, to form at length that 
marvellous compound and complex speck of matter less than the 
suion Of an inch in diameter, which constitutes the active mate- 
rial of each small reproductive particle. This is one way in which 
the properties of the spermatozoon may be accounted for. Nor is it 
beyond the power of the imagination to picture the orderly arrar ge- 
ment and rearrangement of such vast hosts of potential molecules 
as is supposed. No confusion, no jostling of one another, no 
struggling would be seen, for each molecule takes its appointed 
place, in obedience to its own properties, knowing of course the 
position it is to occupy in the complex ranks at each different 
period of its life’s progress, and, never ambitious of discharging a 
higher function than that which it is destined to fulfil, performs 
the important office of transmitting certain peculiarities, important 
or trivial, useful or useless, from the existing to a new being. 
* In Nature for May 1st, Mr Francis Galton very properly remarks 
that the term Mr. Darwin should have employed is “‘ dispersion” not “‘ diffu- 
sion,” and there are other critical remarks which appzar to me equally 
just, 
