THE RETROSPECT. — THE QUERIST. 23 



if they ever do at all. They have never witnessed such a circumstance ; and 

 when, as it is said by thy correspondent John Eose, they were in " consider- 

 able numbers," I incline to believe he may have been mistaken ; especially 

 as food on which these birds feed is plentiful in August, and they need not 

 be driven to seek parasites on the sheep's back. It is notorious that Star- 

 lings feed on grass-land amongst the sheep, and are known to settle on their 

 backs ; and at the time mentioned, the young birds, in their gray plumage, 

 may be mistaken for Thi-ushes. The former are often seen in large 

 numbers ; and the latter, I believe, rarely so. Until I hear of some* con- 

 firmation of his statement, I must believe that thy correspondent was 

 mistaken. — J. J. Fox, Devizes, llmo. 6th, 1854. 



%\t ^wmst. 



Can any of j'our microscopic friends inform me of any good and easj' way 

 of separating Desmidiae from Mud ? 



Of the nature of the starlike bodies in the cells of the stalk of the Nuphar 

 lutea ? 



Of the nature of the perforated cells in the stalk of the Common Peony ? 



Of the nature of the globular bodies in the cells of the testa of seed of 

 Common Privet ? 



Of the minute crystals in the cells of the testa of the seed of Anagallis 

 arvensis ? These are best seen before the seed is quite ripe. Whether the 

 presence of starch is peculiar to certain families of plants ? What is its 

 peculiar use in their economy ? 



Of a mode of making permanent polarizing crystals ? With me, all these, 

 (and I have tried some hundred varieties and combinations,) with some veiy 

 few exceptions, eventually break up. Does this arise from some chemical 

 combination with the Canada balsam in which they are mounted ? 



Why a thin lamina of Mica, placed above a polarizing object, gives a 

 ground differing in colour from that produced when it is placed beneath ? 



Has the beautiful texture of; the Petalonema alata been anywhere figured ? 



What is the name of the Puccinia (?) now found on the leaves of the Rhus 

 Toxicodendron ? 



With regard to Rhaphides, has Professor Queckett given, at the Micros- 

 copic Society, a second lecture upon them ; and pronounced any opinion on 

 their nature, mode of formation, &c. ? I heard his first lecture ; and learned 

 from a friend, some long time afterwards, that he had not then given his 

 second. The list of Polarizing Crystals given in his book, by the Professor, 

 is very incorrect. The Nitrate of Lead, for instance, does not polarize ; and 



