2 74 



NATURE 



{July 2 1, 1887 



my stockings, and walked another three hundred yards on 

 my bare feet. On being taken to the beginning of this 

 trail, or where I had started in my shooting-boots, the 

 bitch as usual set off upon it at full speed, nor did she 

 abate this speed throughout the whole distance. In other 

 words, having been once started upon the familiar scent 

 of my shooting-boots, she seemed to entertain no doubt 

 that the scent of the stocking-soles and of the bare feet 

 belonged to me ; although she did not clearly recognize 

 them as belonging to me when they were not continuations 

 of a track made by my shooting-boots (10 and 11). 



(13) I requested a gentleman who was calling at the 

 house, and whom the bitch had never before seen, to 

 accompany me in a conveyance along one of the carriage- 

 drives. At a distance of several hundred yards from the 

 house I ahghted in my shooting-boots, walked fifty yards 

 beside the carriage, again entered it while my friend 

 alighted and walked two hundred yards still further along 

 the drive. The bitch ran the whole 250 yards at her full 

 speed, without making any pause at the place where the 

 scent changed. This experiment was subsequently re- 

 peated with other strangers, and with the same result. 



(14) I walked in my ordinary shooting-boots, having 

 previously soaked them in oil of aniseed. Although the 

 odour of the aniseed was so strong that an hour after- 

 wards the path which I had followed was correctly traced 

 by a friend, this odour did not appear to disconcert the 

 bitch in following my trail, for she ran me down as 

 quickly as usual. It was noticed, however, by the friend 

 who took her to the trail that she did not set off upon it 

 as instantaneously as usual. She began by examining 

 the first three or four footsteps with care, and only then 

 started off at full speed. 



(15) Lastly, I tried some experiments on the power 

 which this bitch might display of recognizing my indi- 

 vidual odour as emanating from my whole person. In a 

 large potato-field behind the house, a number of labourers 

 had been engaged for eight or ten hours in digging up 

 and carrying away potatoes all the way along half-a- 

 dozen adjacent "drills." Consequently, there was here 

 a strip of bared land in the field about twenty yards 

 wide, and a quarter of a mile long, which had been 

 thoroughly well trampled over by many strange feet. 

 Down this strip of land I walked in a zigzag course from 

 end to end. On reaching the bottom I turned out of the 

 field, and again walked up a part of the way towards the 

 house, but on the other side of a stone wall which bounded 

 the field. This stone wall was breast high, and was 

 situated nearly a hundred yards to windward of my 

 previous course through the potatoes. The bitch, on 

 being led out of the house, was put upon my trail at the 

 top of the field, and at high speed picked out my trail 

 among all the others, following roughly the various zigzags 

 which I had taken. But the moment she gained the 

 " wind's eye " of the place where I was standing behind 

 the wall, she turned abruptly at a right angle, threw up 

 her head, and came as straight as an arrow to the spot 

 where I was watching her. Yet while watching her I had 

 allowed only my eyes to come above the wall, so that she 

 proved herself able to distinguish instantly the odour of 

 the top of my head (without hat) at a distance of two 

 hundred yards, although at the time she was surrounded 

 by a number of over-heated labourers. 



(16) On another day, when it was perfectly calm, I 

 tried the experiment of standing in a deep dry ditch, with 

 only the top of my uncovered head above the level of the 

 surrounding fields. When she was led within two 

 hundred yards of the place, she instantly perceived my 

 odour, and ran in a straight line to where I had then 

 ducked my head, so that she should receive no assistance 

 from her sense of sight. This experiment shows that, in 

 the absence of wind, the odour of my head (and no 

 doubt, in a lesser degree, that of my body) had diffused 

 itself through the air in all directions, and in an amount 



sufficient to enable the setter to recognize it as my odour 

 at a distance of two hundred yards. 



From the above experiments I conclude that this bitch 

 distinguishes my trail from that of all others by the 

 peculiar smell of my boots (i to 6), and not by the peculiar 

 smell of my feet (8 to 1 1). No doubt the smell which she 

 recognizes as belonging distinctively to my trail is com- 

 municated to the boots by the exudations from my feet ; 

 but these exudations require to be combined with shoe- 

 leather before they are recognized by her. Probably, 

 however, if I had always been accustomed to shoot without 

 boots or stockings, she would have learnt to associate 

 with me a trail made by my bare feet. The experiments 

 further show that although a few square millimetres of 

 the surface of one boot is amply sufficient to make a trail 

 which the animal can recognize as mine, the scent is not 

 able to penetrate a single layer of brown paper (10). 

 Furthermore, it would appear that in following a trail 

 this bitch is ready at any moment to be guided by infer- 

 ence as well as perception, but that the act of inference 

 is instantaneous (12 and 13 as compared with 2, 8, and 

 11). Lastly, the experiments show that not only the feet 

 (as these affect the boots), but likewise the whole body of 

 a man exhales a peculiar or individual odour which a dog 

 can recognize as that of his master amid a crowd of other 

 persons (15) ; that the individual quality of this odour 

 can be recognized at great distances to windward (15), or, 

 in calm weather, at great distances in any direction (16) ; 

 and that it does not admit of being overcome by the 

 strong smell of aniseed (14), or by that of many other 

 footprints (4). 



FOSSIL WOOD FROM THE WESTERN 

 TERRITORIES OF CANADA} 



CILICIFIED wood occurs in the country west of 

 ^ Manitoba in the Upper Cretaceous beds, in the 

 Laramie and in the Miocene of the Cypress Hills, and 

 has found its way into the drift. The numerous speci- 

 mens in our collections, picked up on the plains, are thus 

 of little palsontological value, as their sources are un- 

 certain, and it has become desirable to obtain specimens 

 found in situ. A small collection of this kind was made 

 by Dr. G. M. Dawson in the course of the Boundary 

 Survey, and was described in the Report on the 49th 

 Parallel, in 1875. In 1880, Schroeter, in an appendix to 

 Heer's paper on the plants of Mackenzie River, described 

 a few species from the Laramie of that district. More 

 recently, numerous specimens have been collected from 

 beds of known geological age by Dr. G. M. Dawson, Mr. 

 J. B. Tyrrell, and Mr. T. C. Weston, of the Geological 

 Survey, and slices have been prepared by the latter. 

 They include species from the Belly River and Fort 

 Pierre groups, which are Upper Cretaceous ; from the 

 Lower Laramie, apparently a transition group between 

 the Cretaceous and Eocene ; and from the Upper 

 Laramie, which is probably Lower Eocene, though at one 

 time regarded as Miocene. These woods are mostly 

 coniferous, but there are also angiospermous exogens of \ 

 several kinds. In describing them in detail, they are not 

 named as species, but merely referred to the modern 

 genera which they most closely resemble. We thus find 

 in the Belly River series two types of Sequoia correspond- 

 ing to the wood of the two modern species, and woods of 

 the types of Taxiis Salisbiiria or Ginkgo, Thuja, and 

 possibly Abies, along with exogens referable conjecturally 

 to the genera Betiila, Popitliis, Carya, Ulnnis, and Plata- 

 nus. In the Laramie we have a similar assemblage of 

 conifers and exogens, with forms referable to Finns and 

 Abies, and to Jiiglans and Acer among the exogens. 



' Abstract of a Paper by Sir William Dawson, read before the Roj 

 Society of Canada, May 1887. 



