Proceedings of the Polytechnic Association. 8B9 



the bark of tins ])lant and walk over small akazgia sticks. If guilty, 

 lie tries in vain to pass the sticks and falls in convulsions, when he is 

 heaten to death by the savages ; but if innocent, the kidneys will act 

 freely and the poision is thus eliminated. Dr. Frazer found certain 

 twigs of the so-called akazgia of different structure, which did not 

 3'ield the new alkaloid, and it is probable that those natives who 

 have escaped from the ordeal, drank a decoction made from this 

 variety. 



Preservation of Marine Animals. 

 Mr. A. E. Yerrill avers, in the American Naturalist, that he has 

 successfully used gl3'-cerin for preserving marine animals, by which 

 they retain their natural colors nearly as brilliant as in life. The 

 only precaution necessary is to use very lieavy glycerin, and to keep 

 up the strength by transferring the specimens to new glycerin as 

 soon as they have given out water enough to weaken the first, repeat- 

 ing the transfer two or three times, according to the size and number 

 of the specimens, until all the water has been removed. The old 

 glycerin can be used again for the first bath. In many cases the 

 specimens, especially the Crustacea, were killed by immersing them 

 for a few minutes in strong alcohol, which aids greatly in the extrac- 

 tion of water, but usually turns the delicate kinds to an opaque, dull 

 white color, but this opacity disappears when they are put in glycerin, 

 and the real colors again appear. The green shades turn red 

 almost instantly in alcohol, and specimens of this class should be put 

 at once into glycerin. 



Climatic Changes Produced by Trees. 

 The British Medical Journal says the ground on which stands 

 Ismailia, a town of 6,000 inhabitants, was but a few years since a 

 dry, sandy desert, on which rain was never known to fall. All is 

 now transformed. The old, dried up basin of Lake Timsah has been 

 again filled with water from the Nile, by a fresh-water canal ; trees, 

 shrubs and plants of all descriptions grow rapidly wherever the soil 

 is irrigated, and the artificial oasis widens fast. Accompanying this 

 extraordinary transformation of the aspect of the place, there has 

 been a corresponding change in the climate. At the present time 

 Ismailia, during eight months in the year, is probably the healthiest 

 spot in northern Egypt. The mean temperature from June to Sep- 

 tember is 91^ F. ; the four following months 74'', and the four win- 



