0CT03ER I/, I901] 



NA TURE 



601 



guillemots, for I have noticed (he writes) a kittiwake chase away 

 one of the latter from its nest." 



If this be so, may we not doubt the propriety of supposing 

 that a probably not very intelligent bird like the guillemot has 

 a better eye for varieties of egg coloration than the kittiwake 

 or cormorant, which cannot distinguish the strange egg dropped 

 in its nest ? And if the guillemot has a keen eye for colour, and 

 if this faculty be as useful to the bird as Mr. Ussher suggests, is 

 il not remarkable that natural selection should have permitted 

 the speedy obliteration by stains and soiling of such important 

 guide-marks? Is it not also remarkable that the guillemot, 

 which, on the above-stated theory, needs distinctive marks to 

 guide her to her own egg, should so easily dispense with these 

 marks when her egg is hatched and her young one, so like its 

 fellow-chicks, stands before her? 



Why, again, should each guillemot be provided with a con- 

 spicuous private egg-pattern when other sea-birds, her neighbours, 

 have to find their homes without such aid? 



We have no right to suppose that the guillemot needs guide- 

 marks to enable her to perform acts which are simple in compari- 

 son with those performed by many other birds and mammals. 

 The guillemot's egg is stationary. The young of the fur-seal 

 wanders widely amongst thousands of its similar brethren, yet 

 its mother, even after days of absence, never fails to recognise it 

 and will be satisfied with no other. So, too, travellers in the 

 Antarctic tell us that the penguins' of that region have no trouble 

 in finding their ovvn offspring. There is no need, however, to 

 multiply instances of what is a perfectly well-known faculty in 

 gregarious animals. 



I cannot think that this theory of Mr. Ussher's, st easily made 

 and proportionally difficult to disprove, accounts for the facts of 

 the case. 



On the whole, I am inclined to doubt if any conscious act of 

 recognition be involved in the return of each guillemot to her 

 own particular egg ; for we know that many sea-birds, probably 

 fearing the robberies of the larger gulls, do not willingly leave 

 their eggs unprotected, so that m natural conditions a bird may 

 never actually have to find its egg, but rather its mate whose 

 turn of duty has expired. It seems to me, then, highly probable 

 that, if any conscious act of recognition be involved, it must be 

 dependent upon smell or some other kindred sense. 



But surely it is simpler to regard the varied colours of the 

 guillemot's eggs as due purely to a waste product of the bird's 

 metabolism, a product which in some birds, of which the 

 guillemot must be regarded as one, would be forthcoming in 

 abundance at the exciting season of the year, when all the organs 

 of the body are more or less upset by the reproductive processes ? 



If this view be adopted, diversity of colour follows almost as 

 a matter of course. For it is natural to suppose that in a case like 

 this, where eggsare laid side by side in such large numbers, the ques- 

 tion of coloration is unimportant and anycolourisadmissiblewhich 

 is consistent with the chemical constitution of each particular 

 bird. When I look at a series of eggs of the guillemot I am 

 always reminded of a herd of domestic cattle or a flock of barn- 

 door fowl. In these, when no artificial selection has restricted 

 the colour, the variation is extremely abundant. Like that of 

 the guillemot's egg, however, it has its limits, due to the possi- 

 bilities of the chemical combinations in the animal concerned. 

 So that while red guillemots' eggs are rare, blue and green cattle 

 are unknown. Further, while in some cases, as in cattle and the 

 eggs of the guillemot, the variation is rich, in others, as in 

 the ass and the eggs of the hedgesparrow, for instance, the range 

 of variation, for reasons at present unknown to us, but probably 

 differing in each instance, is comparatively restricted. 



In conclusion, I must add that I am in no sense an opponent of 

 the prevailing theories of protective coloration in birds' eggs as a 

 whole. Such protective colouringalmost certainly exists,but I doubt 

 if it be nearly as extensive as is generally supposed, and I 

 would suggest that the coloration is in many cases purely 

 physiological, an aspect of the question which has assuredly 

 been too much nelected. 



Orange River Colony. G. E. H. Barrett-Hamilton. 



Addresses of Authors of Scientific Papers. 

 May I be allowed, through the medium of your columns, to 

 point out the inconvenience that is caused by the omission of an 

 address on authors' separate copies of scientific papers ? 



1 See Racovilza, " La vie des Animaux etdesPlar.tes dansl'Antarctique," 

 published by the Socie'te royale beige de G«^ogra;)hie, p. 51, 1900. 



Several papers have reached me recently containing valuable 

 and interesting results, but there is nothing to guide me in my 

 search either for the authors' addresses or, in some cases, the 

 name of the periodicals in which their papers were originally 

 published. I am unable, therefore, to acknowledge the receipt 

 of their gift, to send anything in exchange, or to enter into 

 private correspondence with them on their results. 



Sydney J. Hickson. 



The Owens College, Manchester, October 4. 



The Recent Inverness Earthquake, 

 In Nati'RE for September 26 it is stated that the recent 

 Inverness earthquake was not felt in Edinburgh or Glasgow, 

 and apparently the Milne seismograph at the Royal Observatory 

 in the former city gave no indication of any movement. The 

 shock, however, was distinctly felt in Paisley, a few miles west 

 of Glasgow. There are in the Coats Observatory here two 

 seismographs. One of these is a Milne, and it gave no record ; 

 but the other, which is Prof. Ewing's, marked the occurrence 

 of the shock. The time as nearly as could be ascertained was 

 ih. 2lm. 35s. The lateral movement was very slight. 



Andrew Henderson. 

 Paisley Philosophical Institution, Paisley, October 14. 



NO. 1668, VOL. 64] 



THE VIRCHO W CELEB R A TION. 



A FEW days ago representatives of the world's 

 science met in Berlin to do honour to one of the 

 world's veteran men of science. The occasion of Prof. 

 Virchow's eightieth birthday was seized by many 

 learned societies and private individuals to e.xpress their 

 appreciation of the great debt owed by mankind to this 

 epoch-making thinker and worker. The Emperor of 

 Germany bestowed upon him the great gold medal, and 

 the King of Italy a picture in which the Professor's por- 

 trait was accompanied by that of his great Italian 

 forerunner, Morgagni. The idea to frame these two 

 scientific men together, whose work, although separated 

 by two centuries of time, illuminated the same branch of 

 knowledge, was certainly a graceful one. 



Prof. \'irchow was the son of a small farmer in 

 Pomerania, and was born on October 13, 1821. He 

 studied in Berlin, and his first appointment was in 

 connection with the Charite, a hospital which has 

 numbered among its staff many men of European fame. 

 Shortly afterwards \'irchow was appointed University 

 Lecturer. About this time he fell somewhat into official 

 disfavour on account, no doubt, of his sympathy with 

 the revolutionary movements of 1S4S. He left Berlin 

 for the quiet University town of Wurzburg. Here he 

 attracted numerous students and workers, and formed a 

 pathological school which, even after he had quitted it, 

 continued to be one of the best in Europe. 



The work by which \'irchow will always be known is 

 his -'Cellular Pathology." As Lord Lister truly re- 

 marked, workers of the present generation cannot con- 

 ceive the efifect which was produced upon the medical 

 world by this book. In 1S26 botanists began to regard 

 plants as collections of cells ; in fact, Schwann firmly 

 established the position of the cell as the unit of 

 vegetable morphology. Owing, no doubt, to the less 

 distinctly defined characters of the animal cell, it was 

 not until later that Kolliker and others extended the 

 cellular theory to animal tissues. \'irchow, in 1858, 

 found a wider application for this theory and demon- 

 strated that pathological tissues also were collections of 

 cells, and that the phenomena of their growth was 

 covered by the generalisation oinfiis celliihi a cellula. 

 From that time till to-day Prof \'irchow has been an 

 active worker in pathology, combining the highest 

 critical faculty with an apparently perennial assiduity. 

 In London he is well known : not many years ago (in 

 1892 ) he received the Copley medal of the Royal Society, 

 and at that time his great achievements weie referred to 



