July 26, 1906] 



NATURE 



299 



be preserved. The fishes collected by Ihe Belgica 

 in the VVcddell Sea were all pelagic. One species, a 

 Ncniatonurus, came from a depth of 2800 metres. 

 In addition to the account of the first deep-sea fish 

 collected within the Antarctic circle, there is an 

 account of a larger collection made in the Magellan 

 Archipelago, accompanied by a bibliography and full 

 account of the fish fauna of that area. The fish are 

 not only described and illustrated with M. DoUo's 

 usual skill and c.ire, but their significance is discussed 

 in I he verv interesting chapters devoted to their zoo- 



logical and geographical relations. M. Dollo main- 

 tains that the Antarctic fish are of modern develop- 

 ment and highly specialised, and are not, as has been 

 thought, a primitive fauna. He discusses the problem 

 of bipolarity, which has commanded wide attention 

 owing to its advocacy by Sir John Murray. M. Dollo 

 maintains that the evidence of the fish gives no 

 support to this theory. Thus he points out that in 

 the .Antarctic area the predominant family of fish is 

 that of the Nototheniidas, whereas in the .Arctic Ocean 

 the dominant group is the Cottidae. In the wide dis- 

 tribution of the Nototheniids in the .Southern Ocean 

 and the South Pacific M. Dollo sees further support 

 of the existence of the assumed Miocene Antarctic 

 continent, connected with New Zealand, Australia, 



-Cryodraco, according 



and South America, but separated from South .Africa; 

 for eleven-twelfths of the Nototheniidae are littoral 

 species, and, according to Dollo, they can only have 

 spread along the former shores of this sunken land. 



J. VV. G. 



YELLOW JACK.' 

 ''PHE main facts established regarding yellow fever 



' and mosquitoes can be summed up in a few 

 propositions. 



(i) The cause of yellow fever is unknown. 



1 Report to the Government of British Honduras upon the Outbreak of 

 Yellow Fever in that Colony in 1905. together with an Account of the Dis- 

 tributini of the Ste^oniyia fas lata in Belize, and the Measures, necessary 

 to stamp ou; or prevent the Recurrence of Yellow Fever. By Rubert 

 Boyce, M.B., F.R.S. Pp. i.\-t-i04+i3 Plates. (London; Waterlow and 

 Sons Ltd., iqo6.) 



NO. 1917, VOL. 74] 



(2) Yellow fever is transmitted by one particular 

 mosquito, known to science as Stegomyia jasciata, 

 and by no other mosquito or in any other way. 



(3) In order to transmit ihe infection, the Stegomyia 

 must have sucked the blood of a patient during the 

 first three days of the fever, not earlier (during the 

 incubation period), and not later. 



(4) The infection is transmitted after an incubation 

 period in the mosquito of not less than twelve days, 

 and the mosquito may still be infectious fifty-seven 

 days after its first infection. 



It is a peculiar fact that although there are 

 nianv species of Stegomyia, so far as is known it 

 is oiily 5. jasciata that is capable of transmitting 

 the disease. If we may accept this as established, 

 it points to a peculiar relationship between the 

 mosquito and yellow fever which is not exactly 

 paralleled by the case of any other disease-trans- 

 mitting agent, be it mosquito, lly, or tick. 



In the case of malaria, filariasis, and trypanosomi- 

 asis there is not this absolutely limited correlation 

 between the disease and the agent that transmits. 

 Malaria we know is transmitted only by mosquitoes 

 of the subfamily .Anophelina of the Culicidse. This 

 subfamily is divided into a number of genera, and 

 not only do different species of the same genus, 

 e.g. Myzomyia cidicilacies and Myzoinyia fuitcsta, 

 transmit malaria, but also species pertaining to dif- 

 ferent genera, e.g. Pyretophorus costalis and .Ano- 

 pheles macuUpennis, or, if we do not accept these 

 as different genera, and classify them all as belong- 

 ing to a single genus, .Anopheles, still we have the 

 fact of transmission by different species. In filariasis 

 the correlation between Filaria and the mosquito is 

 still less definite; thus not only various species of 

 Culex, but various species of .Anopheles all permit 

 of the development of the microfilariae (filarial em- 

 bryos) in their tissues. (It may be well to say in 

 passing that the proof that mosquitoes actually do 

 transmit Filaria is still wanting.) 



Our knowledge of the correlation of trypanosomes 

 and flies, especially species of Glossina, Tabanus, and 

 Stomoxys, is still incomplete. Ngana, the tsetse-fly 

 disease of Africa, is transmitted by species of Glossina, 

 but not by Stomoxys or Tabanus. 

 The trypano.some of sleeping sick- 

 ness is transmitted by Gl. palpalis 

 mainly, but also by other species ; 

 but it is not yet known which 

 exactly these are. 



.Again, in the transmission of 

 various species of Piroplasma by ticks, various genera 

 and species of ticks suffice to transmit the same species 

 of Piroplasma. 



As to the transmission of Spirochaetes by ticks, our 

 knowledge is at present incomplete, and it would 

 be especially interesting to discover if the relation- 

 ship were as strict "as it appears to be in yellow 

 fever, for Spirochsetes (invisible) have been suggested 

 by Schaudinn as the possible cause of yellow fever. 



The fact, then, that yellow fever appears to be 

 transmitted by only one genus of mosquitoes, and 

 only one species in that genus, points to some very 

 peculiar relationship, and would suggest an or- 

 ganism as the cause, of a different kind from any of 

 those we have mentioned, and, indeed, this is no 

 doubt the case, as, if it had not been so, the cause 

 would have been already discovered. 



Yellow fever, then, is transmitted by a particular 

 and practically world-wide mosquito, Stegomyia 

 jasciata. The fact still requires emphasis _ that mos- 

 quitoes only transmit disease from the sick person 

 to the healthy after certain changes have proceeded 

 in the tissues' of the mosquitoes, and that mosquitoes 



