THE LIFE-HISTORY OF THE PILCHARD. 149 
observations, as published previously in our Journal, except that 
after they have been correctly quoted they are called theories 
which differ from those of Concarneau. M. Henneguy has studied 
the question whether any relation could be discovered between the 
varying abundance of sardines and variations in the abundance of 
any pelagic organisms which form their principal food. His results 
were negative. 
The commentary by the writer of the article upon the publica- 
tions which he has summarised is remarkable and surprising. He 
says the contradiction between the results reached on the one hand 
at Concarneau and on the other at Plymouth and Endoume is a 
matter for anxiety as to the reality of the progress made. One is 
obliged, he says, to accord the same degree of confidence to the 
statement of men who devote to the service of truth the same zeal, 
the same loyalty, and the same knowledge. And yet they contradict 
each other, and the conclusion drawn is that laboratory work is not 
adapted to solve the problem of the biology of the sardine. This, 
it seems to me, exemplifies the erroneous way in which scientific 
evidence is usually regarded by practical men, whether on boards of 
authority, commissions of inquiry, or in courts of justice. The opinion 
of one expert is weighed against that of another, and the only com- 
parison by which they are judged is the reputation and authority of 
their respective authors. Therefore if two experts of equal reputa- 
tion give contradictory opinions the result is zero. Now it is 
perfectly obvious that the reputation of a man should depend on the 
truth of his conclusions and not vice versa, and that in a question of 
evidence the reputation of the witness is of no importance if he has 
no evidence to give. But the difficulty is that in the experience of 
men of affairs scientific methods and scientific knowledge are so 
completely excluded that they cannot give due weight to the facts 
on which opinions are based, and cannot therefore judge whether 
one opinion has more foundation than another. In the question of 
the reproduction of the sardine, which to anyone familiar with 
researches on the life-history of fishes is not so wonderfully com- 
plicated, the fact that Prof. Pouchet has not seen the ripe eggs of 
the fish, or the ripe fish themselves, does not in the least invalidate 
the observations of those who have seen them, namely, Prof. Marion 
and myself. 
- However, I have recently been able to add to the observations I 
have previously made on the reproduction and development of the 
pilchard. This year I have for the first time obtained artificially- 
fertilised eggs, and hatched the larve in the laboratory, and suc- 
ceeded in rearing the larve for several days after hatching. 
The eggs were taken from ripe fish obtained on the night of 
