I feel quite set up by finding that after standing about for hours I can walk eight miles without any particular fatigue.  Life in the old dog yet!  Walpole is a capital companion—­knows a great many things, and talks well about them, so we get over the ground pleasantly.

April 20.

There was a long day of it yesterday looking over things in the Exhibition till late in the afternoon, and then a mighty dinner in St. Andrew’s Hall given by a Piscatorial Society of which my host is President.  It was a weary sitting of five hours with innumerable speeches.  Of course I had to say “a few words,” and if I can get a copy of the papers I will send them to you.  I flatter myself they were words of wisdom, though hardly likely to contribute to my popularity among the fishermen.

[On the 21st he gave an address on the Herring.  To describe the characteristics of this fish in the Eastern Counties, he says, might seem like carrying coals to Newcastle; nevertheless the fisherman’s knowledge is not the same as that of the man of science, and includes none but the vaguest notions of the ways of life of the fish and the singularities of its organisation which perplexed biologists.  His own study of the problems connected with the herring had begun nineteen years before, when he served on the first of his two Fishery Commissions; and one of his chief objects in this address was to insist upon a fact, borne out partly by the inquiries of the Commission, partly by later investigations in Europe and America, which it was difficult to make people appreciate, namely, the impossibility of man’s fisheries affecting the numbers of the herring to any appreciable extent, a year’s catch not amounting to the estimated number of a single shoal; while the flatfish and cod fisheries remove many of the most destructive enemies of the herring.  Those who had not studied the question in this light would say that “it stands to reason” that vast fisheries must tend to exterminate the fish; apropos of which, he made his well-known remark, that in questions of biology] “if any one tells me ‘it stands to reason’ that such and such things must happen, I generally find reason to doubt the safety of his standing.”

[This year, also, he began the investigations which completed former inquiries into the subject, and finally elucidated the nature of the salmon disease.  The last link in the chain of evidence which proved its identity with a fungoid disease of flies, was not reached until March 1883; and on July 3 following he delivered a full account of the disease, its nature and origin, in an address at the Fisheries Exhibition in London.

In 1881, then, at the end of December, he went to North Wales to study on the fresh fish the nature of the epidemic of salmon disease which had broken out in the Conway, in spite of being in such bad health that he was persuaded to let his younger son come and look after him.  But this was only a passing premonition of the breakdown which was to come upon him three years after.