EXTRACTS FROM FOREIGN PERIODICALS. 157 



and the largest about two inches, which led me to suppose that they were one or two 

 months old. There were three or four layers superimposed one upon the other ; 

 the horses' feet and the carriage- wheels crushed many thousands. We travelled 

 upon the road, thus covered, at least a quarter of an hour, at the usual pace." — 

 Q What would Mr. M'Adaxi have said to such a road ! We hope there were no 

 ladies in the diligence ! — Ed.] 



4. Remarkable Instance of Intelligence in a Dog.— Mons. Alphonse De 

 Candolle has communicated the following observations on the instinct of ani- 

 mals : — Being last October in the neighbourhood of Aiguesmortes, I had occasion 

 to observe a remarkable instance of intelligence in a Dog. The day was hot, and 

 the season unfavourable, by reason of the trade winds so troublesome on the 

 shores of the Mediterranean. After walking several hours in the desert which 

 separates the town of Aiguesmortes from Carmagne, we arrived at a plain where 

 we found, in the midst of a whirlwind, some remains of a shipwreck. Out of 

 three Dogs which had followed our guide, only two had accompanied us to this 

 spot. Their black hair attracted the rays of the sun, and the poor creatures, like 

 ourselves, seemed to find the sand somewhat too warm to be pleasant. I sat 

 down on a mat half buried in the sand. One of the Dogs quickly conceived the 

 idea of establishing itself near me. It nestled close to a horizontal plank, by 

 way of procuring a little shade, but finding this insufficient, it hollowed the sand 

 until it came to the part moistened by the sea. It then stretched itself with 

 delight in this fresh and shady bed. There, said I, is an undoubted instance of 

 reason. Had it been instinct, every animal of the same species, placed in similar 

 circumstances, would have acted alike. But the other Dog, though of the same 

 race, and also weary, knew not what to do ; it writhed in the hot sand. One of 

 these Dogs evidently remembered that by hollowing the sand-hillocks, a cool and 

 moist part is arrived at,, and it applied the reminiscence to this particular case. 

 It may perhaps be said, that the Dog which made no burrow had never been on 

 the plain, and had therefore had no opportunity of ascertaining the coolness of 

 the sand underneath. But this i3 not probable, since both Dogs had been accus- 

 tomed to the sea-shore. This, again, is another difference between instinct and 

 reason ; instinct acts without previous experience; The Dog of Peccai, the less 

 sagacious of the two, might perhaps one day have learnt to burrow to the cool 

 part of the sand hills. — Bibliotheque Universelle de Geneve. 



5. On the Structure op Teeth. — M. Retzius, in a letter dated September 

 5, 1836, informs us, that he and M. Purkinje had been occupied nearly at the 

 same time, but unknown to each other, with microscopic investigations on the 

 structure of teeth. The observations of the latter anatomist have been promul- 

 gated in the inaugural theses of two of his pupils, MM. Franckel and Ras- 

 chow; M. Retzius has published his own in the last volume of the Transac- 



