November 23, 191 1] 



NATURE 



125 



0-85". At Bidston, two miles from high-water mark, a 

 similar tide caused a deflection of 0-2". From these 

 observations inferences have been made bearing on the 

 selection of sites for an observatory, the difference in elas- 

 ticity of different types of rock, and other matters. 



Reference is also made to tidal-load experiments carried 

 out in Pennsylvanian railway tunnels, and to observations 

 made by Mr. J. J. Shaw with horizontal pendulums in 

 collieries in the Midlands. 



Following this are catalogues of strong shocks which 

 have occurred in the United States of America, Peru, and 

 Chile, together with epitomes of unpublished notes relating 

 to destructive earthquakes received from Secretaries of 

 State of the Foreign, Colonial, and India Offices. All 

 these will be of use, not only to the seismologist, but also 

 to the man of business. 



Lastly, we have a peculiar catalogue, probably the first 

 of its kind. For want of space it only refers to the five 

 years 1899-1903. For these years it gives all the world- 

 shaking earthquakes, whether they originated on land or 

 beneath an ocean. The times at which each disturbance 

 originated, and the latitude and longitude of its epicentre, 

 are specified. Dual or multiple earthquakes are linked by 

 brackets, and the positions of origins are shown on a map. 

 Inasmuch as this catalogue refers to reliefs of strain 

 throughout the whole world, and not simply to earthquakes 

 which have occurred on land surfaces, it seems possible 

 that it may be used as a basis for new investigations. 



A note at the end of the report shows that although 

 records obtained on smoked surfaces are extremely good 

 for large disturbances, they fail to record very small move- 

 ni'Mits. which possibly may represent disturbances which 

 were large at their origins. 



A communication from Prof. H. H. Turner was a note 

 on the periodigram of earthquake frequency. The con- 

 clusion arrived at was that no period of from seven to 

 twi^nty years existed, or was shown in the materials which 

 he had examined. These materials, however, only referred 

 to large earthquakes which had originated on or near to 

 land surfaces. 



Mr. Maxwell Hall communicated a paper on the solar 

 cycle : the Jamaica rainfall and earthquake cycles. The 

 earthquakes observed in Jamaica closely followed the 

 periods of sun-spot activity. 



A paper by Mr. Napier Denison, of Victoria, B.C., has 

 been referred to separately (Nature, November 2). 



John Milne. 



SOME RECENT WORK ON SEX. 



A 



T the Portsmouth meeting of the British Association 

 there were several communications to Section D 

 (Zoology) relating to recent work on sex, an account of 

 which is subjoined. 



Mr. Geoffrey Smith referred to the theory he put for- 

 ward at last year's meeting to account for the effect of 

 the parasite Saccalina upon the sexual characters of its 

 host, the crab Inachas, according to which the develop- 

 ment of adult female characters in infected crabs of both 

 sexes was held to be due to the production in excess of a 

 yolk or fatty material in the blood similar to that which 

 is stored in the ovary of a normal adult female. Mr. 

 Robson's work (see below) shows clearly that the presence 

 of Sacculina profoundly influences the fat metabolism of 

 Its host. Mr. Smith has made observations on the fluctua- 

 tions in growth of the comb of fowls, which demonstrate 

 the close connection between fat metabolism and the 

 development of the female characters. Measurements show 

 that the combs of hens are continually fluctuating in size, 

 the changes being rapid and between wide limits ; a comb 

 may increase 200 per cent, in area in three weeks. It 

 was found that such rapid increase of the comb invariably 

 took place just before a period of egg-laying began. The 

 hen's comb is composed of two walls of fibrous and 

 vascular tissue, between which is a loose core of con- 

 nective tissue, which at the period of ogg-laying becomes 

 infiltrated with fat, and to this cause is due the sudden 

 increase in the mass of the comb. This increase takes 

 place whf^n thr^ ovary is storing up large quantities of 

 yolk, i.r. wIkmi largo amounts of fatty material are being 

 conveyed in the blood to the ovary. Here, then, is another 



instance of a simultaneous effect upon the ovary and a 

 secondary sexual character brought about by the presence 

 of an excess of fatty material in the blood. Mr. Smith 

 suggested that this case is analogous to that of Inachus 

 infected with Sacculina. 



Mr. G. C. Robson described observations, made recently 

 by him in Naples, to test Mr. Smith's theory that Sacculina 

 stimulates the production in the host crab of a yolk-form- 

 ing substance similar to that developed in the normal 

 female and stored in the ovary at the time of sexual 

 maturity. He examined the blood of the crab Inachus, and 

 especially the lipochromes, v>rhich, by reason of their solu- 

 bility in fat, may be regarded as evidence of the presenc 

 of fat. He found a large quantity of fat in the blood ot 

 sexually mature females with ripe ovaries, and also that 

 the amount of fat in the blood of infected Inachus was 

 considerably greater than that in the blood of non-infected 

 males and immature females. The blood of moulting 

 individuals of both sexes was also found to have a high fat 

 content, but not so high as in infected examples and breed- 

 ing females. An increased fat content was also registered 

 in the liver of infected crabs, and there was strong pre- 

 sumption that this was also the case in the breeding 

 female. Mr. Robson also dealt briefly with the changes in 

 colour in the blood lipochromes, and suggested that in all 

 probability the fate of infected crabs is death from starva- 

 tion, owing to their inability to obtain enough foodstuff of 

 fatty nature for their own immediate needs. 



Dr. Cresswell Shearer gave an account of his recent 

 Investigations on the archiannelid Dinophilus gyroctliatus, 

 collected at Plymouth. This species produces two kinds of 

 eggs, some small, destined to give rise to the small and 

 rudimentary males, others almost six times as large, and 

 also more numerous, which give rise to the large females. 

 The two kinds of eggs are laid together. In a few days 

 the males hatch full-grown and sexually mature, while the 

 females leave the egg in a small and immature condition ; 

 just previous to leaving the egg-capsule they are fertilised 

 by the small males. Sections of females at this stage show 

 the sperms collected on the ventral side of the gut at the 

 junction of stomach and intestine, i.e. where the future 

 ovary will appear, but as yet no trace of the latter is 

 visible. The ova appear much later, when the female has 

 grown very considerably in size. Shortly after the female 

 germ cells appear, each is seen to be joined by a spermato- 

 zoon, the head of which becomes imbedded in, or attached 

 to, the nuclear wall. Ultimately the nucleus of each 

 primitive ovum is composed of two portions, one derived 

 from the spermatozoon, the other from the female cell. 

 These two elements do not fuse, but retain their individu- 

 ality throughout the various oogonial divisions (about forty 

 to fifty in all). In the majority of these divisions the male 

 and female portions of the nucleus divide equally, so that 

 a similar amount of nuclear material, both male and 

 female, goes into each daughter cell. Now and again, 

 however, the female half of the nucleus seems to divide 

 before the male portion, so that the latter is, as it were, 

 left behind, and is shut off entirely from one of the 

 daughter cells. Of the two resulting daughter cells onr 

 has, therefore, the whole of the male part of the original 

 nucleus and its share of the female part, while the other 

 has its share of the female part only. This appears to bo 

 the sex-determining factor, for of the two daughter cell'^ 

 the former, which has its share of the fetnalc ntid tlv 

 whole of the male element, becomes the female ngg, whil^' 

 the latter, which has a portion of the female nuclmis onI\ , 

 becomes a male egg. Both kinds of eggs, onre the sox- 

 determining division has taken place, grow rnnidlv, nhsorh- 

 ing and building up into themselves other immature egs; 

 cells with which they come into contact, .ind in which tli-- 

 divisions of the two portions of the male and foninln nuclear 

 substance have been equal. The outcome of tlils process 

 is that the female egg is fertilised, but the ninl.^ . ;;i; is not 

 fertilised in the ordinary sense of the term : but it !•= 

 impossible to speak of if .ns r^allv unf<Mtili'^rd. ns it h.n-- 

 been directly under the iiiflupnco of the spermatozoon in 

 all the oogonial divisions previous to the sex-d*'. 1 miniiu; 

 one. It is only in the late stages, shorflv before ilh f. mnl.^ 

 egg is laid, that the two parts of tin- mirlinis fuse bf-yond 

 recognition. 



Prof. C. J. Patten discussed th<- verii.il-p!uniag<- changes 



NO, 2195, VOL. 88] 



