
May 19, 1923] 
this is certainly an important result. In view of this 
it seems very unfortunate that Prof. Gatenby has 
stated that, apart from Dr. Bowen’s new interpreta- 
tion of the sperm tail, “ he adds nothing new to 
our knowledge of the spermatogenesis of the Lepi- 
doptera.’”’ He considers the value of Dr. Bowen's work 
to lie in the fact that it confirms his own drawings of 
the appearance of the mitosome. After carefully 
ba aad Dr. Bowen’s paper with the original paper 
by Prof. Gatenby (Q.].M.S., 62, p. 407) I really cannot 
agree that there is any confirmation whatever. One 
figure by Dr. Bowen (Fig. 43) superficially resembles 
a corresponding one in Prof. Gatenby’s paper (Fig. 14). 
Otherwise the figures of the mitosome are totally 
different in the two papers. 
Prof. Gatenby has not answered the criticism that 
I have made of his original description of the forma- 
tion of the mitosome. I cannot see how the chromo- 
philic outer surface of a drop—which, of course, has 
an appreciable area—can, by fusion with another drop, 
or even by mere elongation, become transformed 
into a thread-like loop that has no appreciable area. 
He states merely that the mitochondrial vesicles flow 
together, “‘ forming, at first, elongated structures, then 
loops, and finally filaments.’”’ I have pointed out 
(Q./.M.S., 66, p. 665) that I consider the figures that 
accompany this description inaccurate and mis- 
leading. Further, if such a process does take place, 
surely it would be possible to observe the inter- 
mediate stages, and would not these, in any case, be 
some sort of plate work? If Prof. Gatenby would 
enlarge upon his somewhat brief description it might 
help to clear up the differences between our views. 
With regard to the opinion of the late Prof. Don- 
caster on the formation of the mitosome I should like 
to add a few remarks. In 1919 I had the privilege of 
assisting Prof. Doncaster in working out the spermato- 
genesis of the louse Pediculus ce ae We divided 
the work into two, he dealing chiefly with the chromo- 
some aspect, while I dealt mainly with the cytoplasmic 
inclusions. At first Prof. Doncaster was inclined to 
believe that the mitosome was formed in the manner 
described by Prof. Gatenby, and, in fact, in the 
original notes, which I now possess, there are rough 
drawings by Prof. Doncaster figuring the mitosome as 
aspireme. I could not accept this view, and explained 
my conception to him. Ultimately he agreed with 
me, and it was at this time—about May or June— 
that he paid the visit to Prof. Gatenby, and objected 
to the latter’s description of the mitosome of Smerin- 
thus. However, that he was quite prepared to accept 
Prof. Gatenby’s description is shown by the fact that 
in his last book on cytology he gives Prof. Gatenby’s 
account in full and does not, I think, refer to our 
own observations on Pediculus. 
H. GRAHAM CANNON. 

Zoology Department, 
Imperial College of Science, 
South Kensington. 

The Rodier System of Rat Repression. 
In connexion with the article on ‘‘ The Rat and 
its Repression,’ contributed by me to Nature of 
May 20, 1922 (vol. 109, p. 659), I have been favoured 
with a letter from Mr. Wm. Rodier of Melbourne, 
in which he complains that my™attitude to his system 
of rat repression is unsympathetic, or that, conversely, 
he is misunderstood. 
I should esteem it a favour if you would allow me 
to say that I am not unsympathetic to any means 
of destroying the rat—an animal which I, at least, 
consider to be one of the greatest menaces of modern 
civilisation. 
The attitude I take to the ‘“‘ Rodier Method ”’ of 
NO. 2794, VOL. 111 | 
NATURE 
671 

rat destruction is that its principles are so thoroughly 
understood by all who have studied the rat problem 
that I am conscious of no unfairness when I suggest 
Mr. Rodier harms his cause when he asserts that 
those who do not immediately and unreservedly 
become his disciples are necessarily antagonistic, or 
stupid. 
_ The difficulties Mr. Rodier has to overcome are 
such as are presented by the attitude of authorities 
towards putting rats back by rat-catchers who are 
paid to destroy their catches; the attitude of business 
houses when they pay for rat-clearing and find male 
rats turned back; and the plight of boroughs who 
make it their business to destroy female rats, when 
they find their polygamous males mated by females 
from contiguous boroughs where the ‘‘ Rodier Method”’ 
is not in operation. 
The whole question is one of education, and m 
immediate object is to convince the public that the 
rat is one of man’s most dangerous foes, and one 
that is too expensive to maintain. As for the Rodier 
method, I have an open and sympathetic mind ; and 
I would suggest that it would help Mr. Rodier’s - 
propaganda enormously if he could show us good 
results that could be scientifically checked, say in an 
island like Tristan da Cunha, or the Isle of Man. The 
authorities in the former island, where I am assured 
rats climb trees, would doubtless welcome assistance 
to overcome their terrible foes. 
ALFRED E, Moore. 
The Incorporated Vermin Repression Society, 
44 Bedford Row, London, W.C.1, 
April 28. 

Active Hydrogen by Electrolysis. 
In 1907 Fischer and Massenez (Z. anorg. Chem., 
52, 202, 1907) obtained a concentration of 17 per cent. 
by weight of ozone when they electrolysed a solution 
of sulphuric acid, using a very high current density. 
Since ozone can be produced by this method, it would 
seem probable that a high current density at the 
cathode might aid in producing the ozone form of 
hydrogen. When a solution of sulphuric acid is 
electrolysed, using the above principle, the hydrogen 
that escapes at the cathode contains an active con- 
stituent which combines with pure nitrogen to form 
ammonia. Some of the ammonia formed is collected 
in the absorption bulb, but quite a large portion of it 
remains dissolved in the sulphuric acid solution. This 
active constituent in the hydrogen that is evolved at 
the cathode is probably the ozone form, and is 
produced perhaps in a manner analogous to the ozone 
form of oxygen. The per cent. of the active gas 
formed varies with the current density and the 
concentration of the acid. 
Likewise, if a solution of potassium hydroxide is 
electrolysed, using a high cathode current density, 
the escaping hydrogen contains the ozone form which 
combines with pure nitrogen to form ammonia. 
In the electrolysis of the acid solution the escaping 
hydrogen contains a fog which persists after passing 
through the absorbing solution. This fog is similar 
to, but less dense than, the fog sometimes produced 
by ozone when it is bubbled through potassium iodide 
solution. 
This work is a further verification of the theory of 
Dr. G. L. Wendt that tri-atomic hydrogen may be 
produced wherever atomic hydrogen is formed. 
A. C, GRUBB. 
Dept. of Chemistry, 
University of Saskatchewan, 
Saskatoon, Sask., Canada, 
April 18. 
