HARDWICKE'S SCIENCE-GOSSIP. 



from shallow open nectaries, the extremity of the very 

 long proboscis may be observed to open and spread 

 out to some extent, thus enabling an apparently ill- 

 adapted organ to secure a coveted pabulum. 



Whilst sipping the nectar from the leaf-stalk glands 

 of the Guelder-rose, as well as from the stipula-cups of 

 the bush vetch, the ants keep playing their antennae 

 tremulously over the gland, and the cup, and parts 

 adjacent, in much the same fashion as I have 

 observed them do over the bodies of the aphides 

 when attendant on and milking these insects. In 

 these nectar-secreting, insect-attracting leaf-organs of 

 the former plant, which to my mind appear to be 

 simply modified portions of suppressed, or unde- 

 veloped lamina or blade of the leaf, the transparent 

 sweet liquor is secreted by the walls of the entire 

 trough in globules, at first minute but gradually 

 increasing in size, and ultimately running together 

 into one drop, which may fill to the lip this form of 

 plant-nectary ; whilst in very many flowers the nectar 

 is similarly secreted in globules by the entire 

 nectariferous zone or concavity or cup, as the case 

 may be, ultimately running together, less or more. 



I have said above that leaf-stalk glands are not 

 wholly peculiar to the Viburnum Opulus (common 

 Guelder-rose). They are present, though in less 

 numbers, on the stalk of the leaf of the Primus 

 cerasus (wild cherry), at the base of the blade, and 

 not infrequently situated on the blade itself on one or 

 both sides at its base. Here the glands are mostly 

 two in number, often one, sometimes three, and not 

 infrequently are entirely absent ; and are generally reni- 

 form, though sometimes roundish or ovalish. They are 

 fleshy and elevated, as in the Guelder-rose, and freely 

 secrete in globules over their entire summit a trans- 

 parent thin liquor which ultimately runs together 

 into a sheet or drop ; but they have no regular 

 depression or trough, as have those of the Guelder- 

 rose, being simply irregularly and shallowly 

 depressed at the summit — they are less perfectly 

 evolved. Though I have not satisfied myself that 

 these leaf-glands of the wild cherry are insect- 

 attracting, still I suspect they are so, and have 

 reason to expect they will be ; for it appears to be a 

 pretty general law throughout Nature that where 

 food is there will eaters be. 



Smith (" Compendium of the English Flora ") says 

 that there are " two glands on the under side at the 

 base " of the leaf of the Pntmcs padus (bird cherry) ; 

 and Hooker (" Flora Scotica "), that there are " two 

 glands at the summit of the footstalk " of the leaf of 

 this same species of tree. 



Charles Robson. 



We much regret having to chronicle the death of 

 a distinguished botanist and old correspondent of 

 Science-Gossip, Professor McNab, the Scientific 

 Director of the Gardens at Glasnevin, Dublin. 



BIRD-EGG CURIOSITIES. 



IT is a well-known fact that the eggs of many species 

 of birds, such as rooks, guillemots, gulls, 

 thrushes and lapwings, exhibit great want of 

 uniformity in shape, size and colouring ; and it some- 

 times happens that this departure from the normal 

 conditions, especially in background coloration and 

 marking, is so great that a novice might well be ex- 

 cused for supposing that two eggs taken from the 

 same nest belonged to entirely different species of birds. 

 Any one who has been, either in youth or manhood, a 

 collector of bird-eggs cannot fail to have noticed this 

 variation ; yet it is more than probable that the bulk 

 of collectors have left their observations unchronicled, 

 and it is in the hope that further interest may be 

 excited in the subject that we have endeavoured to 

 group and arrange the various cases which have come 

 under our own notice. 



It may be taken as a general rule that the eggs of 

 most birds vary more or less in the above named 

 particulars ; in fact, it is probable that no species is 

 entirely exempt from the liability to these accidents, 

 or defects. Those birds, perhaps, are the most 

 exempt which lay white eggs ; but that even these 

 sometimes depart from the normal state there is 

 ample evidence to show. We have, for example, in 

 our collection, a hen's egg of the usual size and shape, 

 but which is speckled all over in exact imitation of 

 the turkey's ; while brown, of various shades, is of 

 tolerably frequent occurrence in the eggs of the same 

 species. As mentioned above, guillemots' eggs are 

 well known instances of colour variation, specimens 

 varying in background from greyish-white to grass- 

 green. The eggs of the red grouse, the rook, and the 

 plover also vary to a great extent, both in colour and 

 marking. Some of the latter have been procured with 

 a very pale self-coloured background, an abnormity 

 possibly due to abortion, which seems to be one 

 of the mysterious causes of the absence of the usual 

 pigment in egg-shells. A great number of similar 

 instances might be cited did space permit. 



It sometimes happens, though less frequently, that 

 various birds whose eggs are usually bright and artis- 

 tically coloured, will lay pure white ones. We well 

 remember being much puzzled by three white, 

 curiously shaped eggs, which lay snugly in a nest to 

 all appearances that of a yellow-hammer. Having 

 set ourselves to watch, we found that they were 

 indeed the production of that bird ; and subsequently 

 we discovered two or three other nests of the same 

 species, each containing white eggs only. 



We have also taken, three times in succession, 

 from the same gable end of a farm-building (though 

 never from the same nest), house-sparrows' eggs 

 which were quite destitute of colouring. Unfortu- 

 nately, we were never able to determine with certainty 

 whether or not the same bird deposited the eggs. In 

 all probability these white varieties, as well as the 



