208 



NA rURE 



[June 27, 1901 



said to have been observed in birds, viz., that when a hen is 

 fertilised by a cock of another kind the resulting egg is contained 

 in a shell tinted, more or less, like those laid by the cock's 

 own breed. At the time, I must confess, I was rather inclined 

 to doubt if it did really occur, or if it were not a simple rever- 

 sion, or a mistake, when my attention was drawn still closer to 

 the subject by a friend.who had kindly offered to assist in obtain- 

 ing, if it were possible, additional proofs of telegony by first 

 crossing a canary hen with a greenfinch cock and then returning 

 her to her own breed. This was done, and resulted in three 

 eggs being laid to the greenfinch. Their shells were all tinted 

 more like the eggshells of a greenfinch than those of a canary. 

 Two of these eggs were afterwards found to be infertile. This 

 showed that the alteration in the tint of the eggshell had nothing 

 to do with the nature of the ferlilising spermatozoon. But 

 the occurrence of hybrid oochromy could not be said to have 

 been proved, for there is very little difference in the tinting of 

 the eggshells of a canary and greenfinch, and I do not know 

 whether the canary was purely bred or not. 



I was thus anxious to find out for certain whether or not such 

 an occurrence was possible. I therefore obtained three black 

 Minorca hens, which had come of stock that had been purely 

 bred for the last twenty years. The Minorca breed is the oldest 

 variety of the famous Spanish fowls, of which the origin seems 

 older than the recollection of it ! ' These three Minorca hens I 

 penned up alone for more than four weeks, during which lime 

 ihirty-two eggs were laid, and the shells of all of the later ones 

 were of a very pure white colour. 



The reason I had kept them alone for so long a time was 

 that I required eggs entirely free from the intervention of any 

 cock, and the commonly accepted opinion of poultry fanciers 

 seemed to be that a period of nearly three weeks was necessary 

 for the complete extermination of spermatozoa. However, to 

 prevent any mistake, at the end of this time three eggs were 

 artificially incubated for a period of forty-eight hours at the 

 Durham College of Science, and they proved quite infertile. 



After having thus demonstrated that the Minorca egg is con- 

 tained in a pure white shell, I introduced into their pen a buff 

 cock of the Cochin China breed, a breed famous for the brown 

 with which its eggshells are tinted. The second egg laid after its 

 arrival in the pen was provided with a shell of a very decided 

 brown tint, and among a dozen or more laid within the succeed- 

 ing two or three weeks, the shells of several were of a faint 

 brown tint.- I was, however, unable to observe any difference 

 in the microscopic structure of the eggs, such as is described by 

 Ilerr von Nathusius. (See "Dictionary of Birds," by A. 

 Newton, p. 190.) 



This remarkable case appears to me to be an almost incon- 

 testable proof that hybrid oochromy does, at times, occur, as 

 the only other way for accounting for pure bred black Minorca 

 hens laying brown tinted eggs would be that they were reverting 

 to some brown-egg-laying ancestors, a very unlikely supposition I 

 when we remember the age of the breed. 



The next question to answer is — How does hybrid oochromy 

 take place ? I feel quite convinced, both from my own observa- 

 tions and those with the above-mentioned canary, that the tint 

 of the eggshell is not, and cannot be, affected by the nature 

 of the fertilising spermatozoon, and so we must turn our 

 attention to the spermatic fluid, the chemical properties of 

 which, acting in conjunction with those of the products of 

 the shell-gland, will probably be found to be sufficient to cause 

 this change of tint. 



Hybrid oochromy has, in company with a closely associated 

 phenomenon in another kingdom (I refer to Xenia), often been 

 referred to as a case that cannot be explained by the Weismann- 

 ian theory of heredity, i.e. the continuity of the germ-plasm. If 

 the above explanation (and I can suggest no other) of hybrid 

 oochromy should be proved to be correct, it is easily seen to be 

 merely a chemical change and wholly apart from the phenomena 

 of fertilisation. In the same way I should think it is very 

 possible that xenia might be found to be not unconnected with 

 the conjunction of the male and female elements forming the 

 endosperm. It doubtless will be shown before long whether or 

 not these two attempted explanations be correct. They will, 

 I hope, however, tend to lessen the opposition to the Weismann- 

 ian theory by showing how a fact which, at first sight, appears 



1 "The Poultry Book," by Lewis Wright. Popular edition, p. 340. 

 - Since writing the above 1 have incubated two of these eggs and found 

 At first sight this would seem to coniradict the e\pl 



given, but altbo 

 may take pla 



I hold that fertilisatii 



sary, it certainly 



NO. 1652, VOL. 64] 



absolutely antagonistic thereto is found to be in complete 

 accordance with it. It also shows what a deep effect may be 

 induced in living organisms by the interaction of the chemical 

 products of their glands. 



I must here take the opportunity of expressing my best thanks 

 to the Durham College of Science, Newcastle-on-Tyne, for 

 allowing me the ground, cScc, on which to conduct the experi- 

 ment. G. P. BULMAN. 



Newcastle-on-Tyne. 



The Swimming Instinct. 

 I HAVE just tested the inherited powers of swimming in newly 

 hatched pheasants. I find that when placed in tepid water, at 

 the age of about thirty hours, they swim easily with well-co- 

 ordinated leg-movements and show very little signs of distress. 

 C. Lloyd Morgan. 

 University College, Bristol, June 24. 



RECENT SCIENTIFIC WORK IN HOLLAND. 

 TDEGINNING with that which is of most general im- 

 -'--' portance, we draw attention to the recent work of 

 Prof. Hugo de Vries, of Amsterdam. Prof de Vries, 

 who is well known as a botanist and biologist and whose 

 name is familiar to those acquainted with the history of 

 modern chemistry, has just published the first part of a 

 book entitled " Die Mutationstheorie. Erster Band. 

 Versuche 'und Beobachtungen iiber die Entstehung 

 von Arten im Pflanzenreich " (Leipzig : Veit, 1901), 

 containing, as the title indicates, the account of a series 

 of observations on the formation of new species in plants. 

 Starting from the fact, well known to florists, of the ap- 

 pearance of "single variations" in their fiower-beds, de 

 Vnes has been trying to find wild flowers which would 

 show the same phenomenon. Of the 100 species in- 

 vestigated only one appeared to possess the property 

 which was looked for, the CEiiothera Lamurckia/ia, 

 originally from America, but at present growing wild in 

 Holland. Now about ten years ago de Vries transferred 

 specimens of this plant to the botanical gardens at 

 .'Vmsterdam, and up to date he has studied as many as 

 50,000 of Its descendants. 



Of these 50,000 about 49,200 were in no respect 

 different from the original patriarchal O. Lamarckiaiia, 

 showing no tendency towards gradual chang2 in any 

 special direction, but only the common small fluctuating 

 "variations" as regards size and appearance on either 

 side of a normal, in fact resembling in that respect 

 other plants and animals which are left to thetnselves 

 without being interfered with. 



Quite otherwise the 800 other plants. None of these, 

 although appearing spontaneously, could be said to be 

 representatives of the species Lainarckiaiia, from which 

 they were descended. De Vries arranges them in seven 

 distinct species, viz. i of O. gigiw, 56 of O. albida, 350 

 of O. obloni^a, ■^i of O. ntbn/!£>~c'is, 15S of O. nanclla, 

 22 1 of O. lata and 8 of O. scintillans. Now coines the 

 crucial question of the whole investigation. What right 

 has de Vries to look upon the differences between these 

 seven species and the original species as being of a 

 different order from the variations between the specimens 

 of each species, and what entitles him to call these 

 differences mutations as opposed to variations ? The 

 answer is this : a representative of these new species 

 produces descendants the majority of which unmistakably 

 belong to the same species as itself Not all the new 

 species behave in the same way ; as an instance, the 

 only representative of O. gigas was isolated and made to 

 fertilise itself From it were obtained 450 plants, all of 

 which, with only one exception, were O. .i^igi^s, the one 

 exception not being a return to Lainarckiana but belong- 

 ing to a new variety. The plant is a strong one and 

 retains its properties in subsequent generations so far 

 as investigated. 



