Zoology. 157 



time is a most eligible one for all persons who doubt the accuracy of his 

 conclusions to repeat his experiment. — Cond. 



The Crab and the Oyster. — An amusing and instructive correspondent in 

 your Magazine (Vol. II. p. 149.), quoting Carreri Gemelli, says, that the 

 oran otang (5'imia 5'atyEus) feeds on a large species of oyster, and that, 

 fearful of inserting his paws between the open valves, lest the oyster should 

 close and crush them, he first places a tolerably large stone within the 

 shell, and then drags out his victim with safety. Now the oran otang is 

 one of those animals to which Locke would have allowed a certain degree 

 of reason, from the superiority of their instincts ; but what shall we say of 

 the crab (Cancer Fagurus), which has generally been considered so much 

 lower in the scale of animated beings, but which, from good authority, is 

 said to make use of the very same contrivance to accomplish the same end ? 

 The oyster-dredgers on this coast will tell you that one of their greatest 

 enemies is the crab ; and I have been assured by an old dredger, that he 

 had with his own eyes, more than once, seen the crab take a stone in his 

 claw, and insert it between the opened valves of the oyster (O'strea edulis) 

 before he ventured to seize upon his prey. Another man asserted that, 

 although he had never detected the crab in the act, he had frequently 

 found a stone placed between the emptied shells of the oyster. Surely 

 this must be something more than mere instinct, if instinct be, as it has 

 been defined, " A determination given by Almighty Wisdom to the mind of 

 the brute, to act in such or such a way, upon such or such an occasion, 

 without intelligence, without knowledge of good or ill, or without knowing 

 for what end or purpose he acts." — G. M. Lynn Regis, Dec. 1. 1830.,: 



Art. II. Botany. \ 



Absorption by the Roots of Plants. — In the Bulletin Universel, M.Weig- 

 mann has charged me with denying the power of absorption to the roots, 

 and has mentioned a numerous series of experiments in refutation of this 

 supposed opinion of mine. Now, M. Weigmann has all the time been 

 fighting with a phantom of his own creation. About twelve years ago I 

 made some experiments on the fibres of bulbous roots grown in distilled 

 water, such as the hyacinth, Persian iris, and narcissus, and found that 

 such water was saturated with carbonic acid gas, though altogether ex- 

 cluded from atmospheric air. All the inference that I drew thence was 

 merely this, that though the roots might absorb the requisite vegetable 

 pabulum, it was evident that carbonic acid gas was also excreted, and a 

 double current moving in the same channel is a phenomenon by no means 

 incompatible. Even Dutrochet's theory of the circulation of the sap is 

 incomplete without itj for, what becomes of the elaborated excess? — 

 There are egesta in the plant as well as in the animal. About two years ago 

 I put into the hands of my friend P. Neill, Esq., a communication detailing 

 a multitude of experiments on vegetation, with the effects of solutions of 

 lead, arsenic, mercury, copper, iron, &c., with their several fatal results, 

 and the specific periods of time in which vegetation was extinguished. I 

 there prove what has been with M.Weigmann a ivoj^k of supererogation. The 

 respective poisons were found in the stems, &c., of the plant by careful 

 analysis. I requested Mr. Neill to present that paper either to the Memoirs 

 of the Caledonian Horticultural Society or the Transactions of the Wernerian 

 Society, and presume it has been published long ago. In that paper I men- 

 tioned having repeated the late S. Tennant's celebrated experiment with 

 carbonate of magnesia, but with very different results, since vegetation did 

 take place, a fact of immense importance to the agricultural interest. On 

 mentioning this circumstance to Professor Jameson, he told me, in corro- 

 boration of my views, that farmers in the neighbourhood of Kelso were in 

 the constant habit of using magnesian limestone as manure, and found it as 

 good as any other. — J. Murray. Carmarthen, April 2. 1830. 



