Proceedings of the British Association. 581 



upon by fishermen as an indication of the fish being in good condi- 

 tion. Cod were most affected by parasites when in worst condition. 

 Other causes would account better for migration. — Dr. Lankester 

 believed that parasites were rather the result than the cause of disease : 

 a certain condition of the body attacked being necessary to the de- 

 velopement and nutrition of the parasite, and this was the case in both 

 the vegetable and animal kingdom, and with regard to animal and 

 vegetable parasites. When crops were attacked with blight, aphides, 

 &c. the cause would be found in a state of the atmosphere or of 

 the soil, which first made the plant sickly, and then gave rise to the 

 developement of the parasite. — Mr. E. Solly, jun. thought the state 

 of the plant might induce the action of the parasite. He wished to 

 know if any of the members had observed that any of the artificial 

 manures now in use had any tendency to produce plants subject to 

 blight. — Mr. Webb Hall stated, that certain states of the atmosphere, 

 as well as certain kinds of manuring, produced a condition in the plants 

 of wheat, &c. which were favourable to the developement of insects 

 and fungi upon them. He could speak to the effects of particular 

 kinds of manure. — Mr. Babington had seen some corn, a portion of 

 which was watered with pure water, another with nitrate of soda in 

 solution ; the result was that the latter was very much more mildewed 

 than the former. — The Rev. J. Read observed, that it did not ap- 

 pear that inorganic element remained in the plants. He had watered 

 plants with solutions of nitrate of soda, and although benefited by its 

 influence, the ashes of these plants when analyzed did not contain more 

 nitrate of soda than those of plants not so treated. 



Dr. Richardson read a description of a new genus of fishes called 

 Machcerium subducens. The specimen came from Port Essington, in 

 New Holland, and nearly resembled the Echiodon Drummondii, lately 

 discovered in the Irish seas, by Mr. Thomson. This fish must be con- 

 sidered as a sub-generic form of Ophidium, and is very nearly related 

 to the Blemires. 



Mr. Webb Hall exhibited a specimen of the nest of a wasp, which 

 was found attached to a twig within a deserted bee-hive. The nest 

 was about the size of a pigeon's egg, and consisted of two globular 

 layers of membrane, one above the other, with two apertures, the ex- 

 ternal one much smaller than the internal one. In the internal one 

 there was a single tier of cells five or six in number, in which the 

 ova were deposited. — Mr. Babington stated, there were many species of 

 wasp, besides the common one, in this country, that formed pendulous 

 nests, similar to the one now exhibited. 



