PROCEEDINGS OF THE BRITISH ASSOCIATION. 425 



Dr. Traill stated, that having brought the subject before the Wernerian 

 Society of Edinburgh, General Wright, who had been in Persia, confirmed the 

 observation of his informant. 



The President remarked that among the specimens exhibited by Dr. Traill 

 there were two genera (Argas and Ixodes), and that if they were both poisonous, 

 it would lead to the supposition that the whole family of Ixodidce were poisonous. 

 He had seen insects of this family in Cuba, where they attacked Horses,* but so 

 far from being poisonous, they were thought to be beneficial to the animal. 



The Rev. F. W. Hope observed that he knew the Horses in the Island of St. 

 Domingo were infested with a species of Ixodes, which attacked their ears, but 

 was not aware that it was poisonous. 



Mr. Gray then brought before the meeting a notice of experiments on the repro- 

 duction of insects by Galvanism, performed by Mr. Children. He stated that these 

 experiments were undertaken in order to ascertain the correctness of the results of 

 some experiments by Mr. Crosse, in which he supposed he had organised or revivified 

 insects by the power of Galvanism. The greatest care had been taken that the 

 circumstances under which the experiments were performed should resemble those 

 described by Mr. Crosse. A solution of Silica was obtained from Mr. Garden, 

 and submitted, both with and without access to the atmosphere, to the action of 

 a powerful galvanic battery; the intensity and quantity of the galvanism were 

 varied, but no insects were obtained. 



The Rev. F. W. Hope thought it quite impossible that insects so high in the 

 scale of organisation as those described by Mr. Crosse should be produced. If 

 matter had been vitalised, we should have looked for it in its simplest and most 

 elementary forms. The insects said to have been reproduced were a species of 

 Acarus. The ova of these insects might have been accidentally introduced into 

 the solution, and have become developed during the course of the experiment. 



Mr. Gray related some instances of the ova of insects becoming developed 

 after exposure to circumstances that might be supposed would destroy them. 

 The larvae of the Common Fly were not destroyed by exposure to prussic acid. 

 The ova of various insects which must have been confined for several years, had 

 produced larvee on exposure to moisture. 



These remarks led to a discussion, in which Professor Graham, Mr. Gray and 



* At a subsequent meeting the President stated that those Ixodes which attacked Horses in 

 some instances literally covered the animal. They inserted their serrated proboscis into the 

 animal's skin, and remained fast attached to it for some days, when they dropped off, leaving their 

 rostrum behind. If the insect was captured at this stage of its existence, it was generally found 

 full of ova, which did not escape at the termination of the oviduct, but at the orifice which had 

 been produced by the breaking off of the rostrum. After falling off the Horse, the insect generally 

 retreated under stones, wood, &c, where it deposited its ova. 



