After having upset accepted understandings about the salmon, Sir Herbert Maxwell made experiments among the trout, and then published heretical speculations. He had some artificial Mayflies dyed red, and some dyed scarlet; cast them upon streams, such as the Mimram, the trout in which are spoken of as having reached the wariest familiarity with the angler's wiles; and found just as good sport as he could have hoped for had the flies been of the greenish-yellow hue. This was startling news. It disturbed many minds beyond all hope of reassurance. If trout could not tell red from yellow, or did not care whether a Mayfly was one or was the other, clearly all the thought and pains embodied in the manifold treasures of one's fly-book were wasted, and pride in one's beautiful possessions must crumble in chagrin. Why search the Indies and the Far East for hackles if feathers which would do as well were to be found in the nearest poultry-yard ? Indeed, if trout did not know one colour from another, or paid no attention to colour at all, was not the angler's subtlety a delusion, and the sport reduced to the level of the laborious handicrafts ?
It has taken one a long time to recover from these misgivings; but hope revives. The trout that took the red and the scarlet Mayflies must have been in a state of panic fearlessness. To venture such a thought may at first seem begging the question ; but that is perhaps because, living in water, where we cannot tarry to observe them, trout in some of their moods are beyond our range of knowledge. To say of a fish whose conduct is irregular that he must be off his, head seems even more empirical than hastily saying the same thing of a man whose actions differ from one's own. Of this I am conscious; and it is not upon an irrational suggestion of mere bewilderment that I rely in hoping to explain away the ruddy Mayflies.
Wild animals whose habits we can observe closely and continuously sometimes behave in a manner which at first sight is quite unaccountable. The ptarmigan are so much in dread of man that they stay habitually on the least easily accessible boulders at the mountain tops ; yet if you come upon a covey of them unawares, they do not take the trouble to fly. In summer and autumn the red-deer, which can scent a man two or three miles off, will, the moment they are conscious of his neighbourhood, trot other miles away from him; yet when the snows of winter cover the heather, they will come down into the glens and beg fodder from the farmers. At all times of the year, sparrows, finches, and other such small birds fight shy of man ; yet if in winter, when food is scarce, you throw aniseed to them, suddenly, with a wild whirring of wings and other signs of uncontrollable excitement, they will flutter about you, some of them even resting on your shoulders to ask for more.
Why should it be considered absurd to assume that trout may be occasionally capable of a similar departure from their habitual reserve? If they are not, they differ from most other wild animals with whose instincts we have a fairly complete acquaintance; and to assume this would be more flagrantly unnatural than assuming that, in common with animals of other species, they do sometimes lose their judgment and discretion. Besides, the natural assumption, although not quite consciously, is already made by anglers generally, and is even expressed in phrases which, early in June, inevitably reappear in all the journals of sport. We hear of " the Mayfly Carnival": what does " Carnival" denote if not a hilarious outbreak of reckless indulgence ? We hear also of " the duffer's fortnight" : what can these words mean save that during the period of the Mayfly the trout are so abandoned in voracity that the need for skill in luring them is for the time gone ? As food for the fish the Mayflies are extraordinarily stimulating. When they are thoroughly " up " and fluttering thickly about the surface of the stream, all the trout in the water are near the surface, gobbling; even the largest fish, which at ordinary times lie low unseen, shoulder the youngsters out of the way and scour about ravening on the delicacies of the season. Any one who has witnessed the wonderful excitement in a river during the Mayfly time will readily realise that then the fish will rush at anything which seems alive.
After all, then, as a test of the trout's sense of colour, Sir Herbert Maxwell's experiments are not by any means conclusive. According to general experience, the sense of colour at ordinary times is marvellously acute. Who cannot recall a day on which the trout showed a preference for some fly so marked as to be practically absolute ? The fact which is implicit in that question need not be dwelt upon. It is one of the most familiar phenomena of the sport. If the fish are rising at a dark dun, a pale dun will not do. If you have been catching trout after trout on a woodcock with hare's-ear, you may try a woodcock with red hackle in vain. The presence or the absence of a touch of tinsel on a hook often makes all the difference between success and failure. Some days the tinsel is desired; on others it is forbidding.
The same consideration applies to every fly in the richest stock. Each has its day or days, its hour or hours; and to these times alone is it opportune. There are dozens of the flies, a few of them made in imitation of insects found on certain waters only, most of them for use anywhere in Great Britain and Ireland. Think, then, of what a range of knowledge is implied in the fitting choice of lures to be mounted on the cast. Sometimes, by bringing out the ephemeral creatures in their due season, Nature helps: you see on the water, or flying about just above it, the insects which the lures on the cast should resemble. Sometimes Nature withholds this help: an untimely frost, or even a less severe lack of warmth, delays the hatching.
Often, also, Nature plays a prank which is injurious to the modern doctrine that floating flies, to be cast over rising trout, are the only proper lures. Even on the warmest day of summer, a chill air is often not far away. It is wandering about on the hillsides or on the meadows; or perchance it lurks in some copse by the side of the stream. In any case, the myriad family of insects newly born among the reeds are liable to be caught in it; then they are numbed, fall upon the water, gradually sink a little below the surface, and are carried down the stream. The trout take them without breaking the water. That explains why the Dry-fly doctrine is far from being of general application. It has been fashionable within the last ten years. Articles without recorded number, and even a few books, have been written in its praise. It has received the unqualified approval of sportsmen so eminent as Mr. Senior and Lord Granby, together with the modified approval of Sir Edward Grey and Mr. Sydney Buxton among many others ; but it holds a large element of fallacy. Often most of the flies provided by Nature are half-drowned. Half-drowned, then, as a rule, should be the aspect of the lures offered to the trout by the angler. Other considerations leading to that conclusion will be set forth anon.