HARDWICKE'S SCIENCE-GOSSIP. 



215 



Squirrels in Winter.— To doubt that ihe 

 squirrel hibernates, because it is not infrequently seen 

 abroad in the winter, appears to me rather like 

 questioning whether bats are strictly nocturnal, on 

 the strength of the few notes recently inserted in 

 Science-Gossip relative to their flying in sunlight. 

 This last occurrence, by the way, is far more common 

 than any of the correspondents who have sent their 

 observations, seem to suppose. I believe no summer 

 passes without my seeing instances of it. At times, 

 a bat will be noticed for several successive days, 

 hawking round the same spot in the brightest hours 

 of sunshine. As to the squirrel, I am well aware 

 that he may be seen in every month of the year ; but 

 the marked absence of regularlity in his winter 

 appearances can only, I think, be explained by still 

 considering him to a certain extent a hibernant. In 

 a wooded country frequented by squirrels, a person 

 who has observed their habits can visit them any day 

 he pleases throughout the summer months, with little 

 fear of failing to find them at home. The litter which 

 a squirrel makes under the tree wherein his daily 

 meal is despatched is quite prodigious ; so that even 

 a casual walk through the grove tells you in what 

 trees squirrels have been recently feeding ; and where 

 the fragments are freshest, a squirrel will be found. 

 But of course you must go at his meal-time. The 

 hour of his afternoon repast is from 3.30 to 4.30, and 

 during that period the squirrel's acquaintance can be 

 cultivated ad libitum. Day after day you will find 

 him in the same tree — a larch if it be x\ugust, a 

 beech if it be September — crunching the cones of the 

 one or the mast of the other, and pelting the 

 fragments down upon you as you sprawl on the sward 

 beneath. I have spent many a pleasant half-hour in 

 receipt of these attentions. In winter, you come 

 across the squirrel by chance, or stumble upon traces 

 of a squirrel feast (under Scotch firs generally) fresh 

 enough to inform you that a squirrel has been there 

 not longer ago than yesterday afternoon. But go to 

 the spot to-morrow, and you will find the very same 

 patch of fragments, only less fresh ; not in the least 

 augmented by further chippings. Or go where you 

 met the squirrel himself, and if you expect to meet 

 him again you are more than likely to be disap- 

 pointed. Why, then, cannot the squirrel be traced 

 in winter as well as in summer? I think we may 

 answer, because the squirrel only occasionally wakes 

 up to life in the winter, and the fact that he has 

 dined once in such or such a tree is no indication of a 

 likelihood of his returning thereto. Yet I am far 

 from questioning that these frequent interruptions of 

 the squirrel's torpidity may indicate a gradual dying 

 out of the hiberuatory habit. If I may speak from 

 the local conditions of my own neighbourhood, where 

 squirrels for the past twelvemonth have been some- 

 what common (result of some spontaneous migration) 

 no animal could have less need to hibernate. 

 Abundance of food surrounds him at all seasons. 

 Indeed, it is worth mentioning that at least one 

 favourite squirrel-food, the larch-cone, is never out of . 

 season. I can give a curious proof of this. During 

 the latter part of last August, 1890, all the squirrels 

 about here seemed to be feeding exclusively on the 

 green larch-cones. It is now August 5th, and the 

 squirrels are nearly all feeding on the old brown larch- 

 cones, remnants of the same crop that afforded them 

 food a year ago. This is not because the green cones 

 are not ready ; for as long ago as July 12, the 

 squirrels about Bray, Co. Wicklow, were devouring the 

 green larch-cones, and the cones here are as forward 

 as those at Bray. It is therefore plain that one crop 

 of larch-cones continues to be good feeding for more 

 than a whole year. The squirrel, of course, will at 



frequent seasons desert the larches for other forms of 

 food ; during the whole of September, and greater 

 part of October he seems to subsist entirely on beech- 

 mast ; in winter he loves haws and pine-cones, in 

 spring the tender shoots of the spruce. But, when- 

 ever he is hard up, he has an unfailing friend in the 

 larch ; and therefore, if the squirrels in this part of 

 Ireland have need to hibernate, it is from some 

 different cause than that usually assigned, the scarcity 

 of food.— C. B. Moffat, B ally hy land, Co. Wexford. 



Grapes in the Open Air. — F. Y. wishes to ask 

 the scientific reason for exposing hot-house grapes to 

 the night air, for the purpose of colouring them. 



CONCHOLOGICAL SOCIETY'S JOURNAL. — As a 



member of the Conchological Society, may I venture 

 to suggest that the numbers are much damaged 

 for neat binding by the quantity of glue which is 

 used on the backs ; they are pinned as well, and in 

 most cases the pins would be sufficient, and ensure 

 neat binding afterwards. I bind my own magazines 

 (as an amateur), therefore I speak practically on the 

 subject. — Alary Heitla7id. 



Optical Effect. — The " black branched object 

 which has been popularly likened to the ramifications 

 of the brain" is known as the "figure of Purkinje." 

 Besides being produced in the manner described by 

 H. J. I., the phenomena may be quite as easily 

 noticed by bringing a sli;,'ht pressure to bear on the 

 eyeball. It is purely a mechanical effect, and is easily 

 explained. Rays of light falling on the eye impinge 

 on the anterior part of the retina, pierce the layer of 

 ramifying fibres of the optic nerve, and the whole 

 strata of the retina, and then act on the bacillaiy 

 layer, which is composed of minute structures termed 

 rods and cones. In the experiment described by H. 

 J. I., the vision becomes yellowish-red, and is 

 peculiarly marked by dark ramifications which really 

 indicate the branches of the retinal artery. The eye, 

 it will be noticed is directed to the darkest part of the 

 room, while the candle is so held that the light falls 

 on the retina at a slanting angle. This shows up the 

 " branched object," which is none other than the rami- 

 fying blood-vessels intervening between the rays of 

 light, and the bacillary or sensitive layer behind. 

 The experiment depends entirely for its success on a 

 slow movement of the candle. This stopped, the 

 figures disappear.— 7^r^^. H. Davey. 



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