ZOOLOGY. 333 



Thirdly. The author concludes that his experiments do not pre- 

 sent any facts which appear to sanction the opinion, that insects are 

 deprived of life with much greater celerity when pierced by the fangs 

 of spiders than when mechanically lacerated to the same extent in 

 other ways. It is true, however, that the catastrophe is greatly ac- 

 celerated, if the spiders maintain their hold for some time, but this is 

 to be attributed to the extraction of their fluids by deglutition into the 

 stomachs of their adversaries. 



Fourthly. In his experiments on inanimate substances, Mr. Black- 

 wall found that litmus paper presented to spiders belonging to several 

 genera, when they were in a state of extreme irritation, and moistened 

 by the transparent fluid which issues under such circumstances from 

 the fissure near the extremity of the fangs, invariably became red as far 

 as the fluid spread, clearly proving that this secretion, although taste- 

 less, is an acid. On the other hand, the fluid that flows from the 

 mouth, as also that contained in the stomach, and that which is dis- 

 charged from wounds inflicted on the body or limbs, were found by 

 the same chemical test to be alkaline. Turmeric paper was rendered 

 brown by the application of the fluids from the mouth and stomach, 

 and restored to its original color by the agency of the fluid secreted 

 in the so-called poison gland, thus affording complete proof of the 

 respectively alkaline and acid natures of these several secretions. 

 Mag. of Nat. History. 



CONSUMPTION. 



AT the last regular meeting of the National Institute, Dr. Riofrey, 

 of Paris, made some very interesting and scientific observations on 

 the subject of consumption. Post mortem examinations had shown 

 that nature, under certain circumstances, cures the disease. It was 

 important to inquire what these circumstances were. From the ex- 

 tensive field of the author's remarks on France, Holland, and Great 

 Britain, it appeared that a cure was effected whenever thin and atten- 

 uated men changed their climate and habits, one or both, and in con- 

 sequence developed a tendency to become fleshy; he considered a high 

 northern and southern latitude alike favorable. He named the Ameri- 

 can coasts from latitude 55 degrees north to 17 degrees south as con- 

 sumptive latitudes. He deemed all the temperate latitudes unfavor- 

 able. 



Prof. Maury said that latitude 17 degrees south was precisely the 

 point where the trade-winds, relieved from their moisture by the An- 

 des, produced a dry air. Dr. Gale said that Natchez was a favorable 

 point, in the Mississippi valley, for consumptives; yet Natchez had a 

 very humid climate. Dr. Borland (U. S. Senate) confirmed these 

 views. The nights were exceedingly damp. The wind blew up the 

 river, bringing the dampness from the Gulf. Prof. Henry attributed 

 the deleterious effects in consumption rather to the amount of change 

 in the thermometer at given points than to the actual state of temper- 

 ature. Prof. Maury represented the coasts of Patagonia as literally 

 submerged with rain; twenty-one feet of rain had actually fallen in 31 



