27 



Mr. Nelson said he had not yet had the opportunity of doing so, and had 

 not referred to the matter because his paper was written before his return 

 to town, and, therefore, previous to his having been able to see these lenses. 



The President was sure that all present would join in thanking Mr. 

 Nelson for his two very interesting communications, relating as they did to 

 subjects upon which some people at least had rather misty ideas. He had not 

 only given them a very clear description of what was meant by the secondary 

 spectrum, but had in his second paper introduced them to what appeared to 

 be an interesting method of obtaining some idea as to the combinations of 

 an objective. 



The thanks of the meeting were unanimously voted to Mr. Nelson for his 

 communications. 



The President said he had brought down to the meeting an object which, 

 he thought might be interesting to some of the members. It was not 

 strictly microscopic, for although it was one of his " pets," it was a 

 creature of appreciable size — one of the Argasidas, the Persian Argas 

 originally introduced to the notice of zoologists in 1823 by Fischer, who 

 published an account of it in the Transactions of the Academy of Moscow. 

 Fischer had been travelling in Persia, and had collected a large amount of 

 information on Natural History subjects, and he gave a terrible account of 

 this creature, whose bite, he said, produced violent fever, madness, and 

 sometimes death in the course of 24 hours, and that it was particularly 

 fatal to strangers. These remarks got abroad, and appearing in various 

 works on Natural History and Entomology, became generally received as 

 facts, especially as they appeared to receive confirmation from time to time 

 by the reports of other writers. In 1858 Heller managed to obtain some 

 specimens, his object being to study their anatomy, and he gave the results 

 of his observations in the Transactions of the Vienna Academy of Sciences, 

 giving also some very good figures of the creature. Nothing more seemed 

 to transpire on the subject until 1878. A few years previous to this date 

 the Shah of Persia wrote to the French Government to ask for a physician 

 to be sent out to him at Teheran, and in response to this request Dr. 

 Tholozan was appointed to the post, and was asked to collect and send 

 home specimens of the Argasida?. This he accordingly did, collecting 

 them from Miana and other places. At Miana he found that at the present 

 day they did not bear such a terrible reputation as that given to them by 

 Fischer ; they were found in the neighbourhood, chiefly upon sheep, but 

 were not thought to be dangerous. However, at another place he found 

 that they were not only considered dangerous, but that they were called by 

 the natives Guerib-gueZyOV " Strangers beware." Dr. Tholozan sent them to 

 Laboulbene, and soon after they arrived he sent them on to Megnin for 

 examination. Megnin was busy at the time, and put them aside in a 

 drawer until he had time to attend to them, but forgetting what he had 

 done with them, and being unable to find them, he had to tell Laboulbene 

 that they were lost, and he in turn not liking to ask for more, the matter 

 for the time ended there. Three and a half years afterwards, however, 



