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collected by the aborigines, who thus evidently profit by the 

 labours of the ants. 



The fact mentioned by Pliny is therefore absolutely correct ; 

 but what is very curious is that but a single species of ant (the one 

 mentioned above) engages in this peculiar labour, and that this ant 

 is found only in North America (Colorado, New Mexico, etc.). 

 Hence the dilemma. Either Pogonomyrniex occidentalis in the time 

 of Pliny inhabited the Indies properly so called (Hindostan), from 

 whence it has entirely disappeared since that epoch, since it is very 

 certain that it is not found there at present ; or else it always 

 inhabited North America solely, and then Pliny's narrative, too 

 precise to have been manufactured, would necessarily have been 

 derived from travellers that had already visited America at that 

 remote epoch. 



The first hypothesis seems to us inacceptable, for, although it 

 is true that certain species of ants (such as Atta septetitrionalis) 

 seem to be on the road to degeneracy, it can be asserted that ants 

 are in no wise creatures whose species can totally disappear from a 

 continent in a few centuries ; and if, consequently, we must admit 

 the second hypothesis (which would make the " Northern Indians," 

 vaguely mentioned by Pliny, to be " North Americans" ), we must 

 see therein a very unexpected argument, which we offer in support 

 of the opinion that the ancients were acquainted with certain 

 parts of America. — Scientijic Ajnerican. 



A Course of Practical Histology. By Edward Albert 

 vSchafer, LL.D. , F.R.S., etc. Second edition. Large cr. 8vo, pp. xi. — 298. 

 (London: Smith, Elder, and Co. 1897.) Price 7/6. 



In this useful book intelligible directions are given for the suitable prepara- 

 tion of the animal tissues intended either for immediate study or future refer- 

 ence. The author has taken care to select methods upon which, in his expe- 

 rience, complete reliance can be placed. 



In an Introductory chapter an account is given of the several parts of the 

 microscope, and the purposes for which they are intended, and of the instru- 

 ments and methods of staining and otherwise preparing tissues which are in 

 more general use in Histology. Instructions are also given for measuring and 

 for delineating microscopic objects. There are a number of good illustrations. 

 We feel that we can confidently recommend it to all working microscopists. 



