January 6, 192 1] 



NATURE 



601 



tned invasion of migrating springbuck which 

 uould otherwise have utterly ruined the crops in 

 the district (vol. iii., p. 92). 



Man, however, is not altogether to blame for 

 he scarcity of some of the larger animals of 

 >i)Uth Africa. Rinderpest undoubtedly played 

 hav<)<- among them, and large numbers of kudu, 

 .African buffalo, and others are known to have 

 been decimated by this dread disease. 



The smallest of the South .African antelopes, 

 about the si/e and weight of a large hare, is the 

 blue duiker. It is wonderfully alert, and pos- 

 ses.ses the senses of sight, hearing, and scent in 

 a high degree of perfection ; so much so, indeed, 

 that the bushbuck is believed to have made some 

 ■i)rt of compact with it for their mutual protection 

 vol. iii., p. 42). 



The fourth volume deals with the insectivores. 



moles differ from them in structure and colour, 

 and have been placed in a distinct family. It 

 is worthy of note that an extinct relation of 'this 

 isolated group (Xecrolestes) has been discovered 

 in the Santa Cruz deposits of Patagonia. The 

 several curious burrowing rodents- viz. the bles- 

 mol, mole rat, and sand mole — are sometimes mis- 

 taken for true moles. They belong to quite a 

 different order, and feed on roots, whereas the 

 golden moles are insectivorous. The author's 

 statement (vol. iv., p. 170) that two species of 

 the octodont tribe of rodents inhabit South .Africa 

 requires some modification, for probably neither 

 of the.se should be included in the familv Octo- 

 dontida'. Right at the end of the fourth volume, 

 instead of at the beginning of the work, the author 

 explains what is meant by the term "mammals." 

 We have alreadv commented on the author's 



Kui. 2. — Aard^a^k. From *' The Natural Hi\torv of South Afriia. 



roiiciii^, \\h;iUs ;iiui their kindred, and the eden- 

 ttes. One of ihc most interesting features of 

 iie South .African fauna is the presence of 

 'le golden moles. Though very simitar in 



ibif to their Knrnpcan relations, the golden 



charm ul >tsL-, and throughout his work he makes 

 one feel that he has acquired his extensive know- 

 ledge in the open field and ha-"! a personal 

 and intimate acquaintance with most of the species 

 he describes. 



Science of Ventilation and Open-air Treatment. 



TOURING the war it was found that the phy.sical 

 ' -' condition of many of our young men was 

 .ir from satisfactory, and there can be but little 

 !()ubt that one of the contributory causes to this 

 tate of affairs was the ill-ventilated dwellings and 

 t ictorics in which such men frequently had to 

 live and work, combined with a lack of oppor- 

 tunity or disinclination to take exercise. For 

 example, in one region of Fngland, of 200 youths 



XO. 2671, VOL. 106] 



of eighteen to twenty years of age examined and 

 rejected, no fewer than eighty-five failed to pass 

 on account of poor physique and other physical 

 defects. 



One important cause of defects of physique and 

 of degeneration is the effect of occupation on 

 workers. "One of the most striking features of 

 the report of grading in the industrial districts is 

 the rapid fall of the numbers of the young men 



