Aug. 1, 1S68.] 



HARDWICKE S SCIENCE-GOSSIP. 



183 



ON THE FORMATION OF FERN SEEDS. 





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Fig-. 197. Fern Spores. 



rpHE seeds or spores of ferns are contained in 

 -*- little vessels named theccr, which are generally 

 gathered together in clusters named son (fig. 3), 

 and most commonly covered with a thin transparent 

 covering termed the indusium, which is formed of a 

 single layer of cells. In the Maiden-hair, Adiantum 

 cctpillus veneris (which I have chiefly studied on 

 account of the transparency of its fronds), the 

 indusium is formed by the out-growth and over- 

 lapping of the edge of the pinnule (fig. 1). Soon 

 after the indusium begins to be formed, the thecse 

 appear between it and the leaf as small green cells 

 full of granular matter (fig. 2). In a little while 

 these develop a cellular covering (fig. 4), and a 

 peculiar disposition of cells, which afterwards form 

 the spring by which the spores are eventually 

 liberated from the thecal. 



As the thecae advance towards maturity, there 

 appear within them small round cells (fig. 5) de- 

 veloped from the granular matter ; these by subse- 

 quent cell-division become the spores. In their 

 early stage the spores are transparent, but afterwards 



become opaque and dark coloured. The young 

 spores of the Maiden-hair are represented at fig. 6 ; 

 of the Oak Fern, Polypodium dryoptcris, at fig. 7 ; 

 and of the narrow Prickly Fern, Polystichum loba- 

 tum, at fig. 8, in which the formation of the spore 

 from the division of the round cell is very evident. 



The young spore of the Male Fern (fig. 9) displays 

 a nucleus; this I have not observed in the spores of 

 other ferns; c is the ripened spore. A band of 

 cells nearly surrounding the thecse forms a kind of 

 spring, the growth of which seems to be thus : — 

 The adjacent cell-walls are at first partially ab- 

 sorbed, so that the whole spring becomes one cell, 

 and in this stage contains starch granules (,fig. 10). 

 Then the rings which remain at the junction of the 

 cells are strengthened on three sides with secondary 

 deposit ; and become like arches sustaining the 

 outer cell-wall, which seems gradually to dry in and 

 produce a tension of the whole. As the spores 

 ripen, the sides of the thecse become thinner and 

 weaker, until the tension of the spring overcomes 

 their resistance, and scatters the spores on every 

 side. J. S. Tute. 



A CENTURY AGO. 



UNDER this title a correspondent gave us last 

 year (see p. 127 of Science-Gossip for 1867) 

 some interesting extracts from a work on natural 

 history published in 1763. Just before reading 

 these I had, curiously enough, accidentally met 

 with an old book, forming vol. v. of a larger work, 

 on the " Natural History of Waters, Earths, Stones, 

 Fossils, and Minerals, with their Virtues, Pro- 

 perties, and Medicinal Uses," &c, by R. Brookes, 

 M.D. This, too, was printed in 1763, and at the 

 Bible and Sun, though this office is therein stated 

 to be in St. Paul's Churchyard, and it was printed 

 for J. Newbery, not for C. and R. Ware. I thought 

 at first it might possibly be a portion of the same 

 work from which Mr. Alleu quoted ; but, however, 

 that is of no consequence. The statements put 

 forward in it are, perhaps, not so absurd as those 

 he produced, but they are certainly interesting. 

 My book commences with a full and particular 

 account of the various medicinal waters of England, 

 their properties, and the doses prescribed for 

 different complaints. These said doses are somewhat 

 alarming to us of the present day, especially if we 

 believe in homoeopathy, a quart or two being con- 

 sidered a very moderate quantity. The Bulwich 

 Water, which "has a brackish taste, with a little 

 bitterness in the throat," cures several ailments, if 

 taken in a dose of three pints a day at first j but 

 this " should be increased every day, till it comes to 

 eight or nine pints " ! 



"At Aucliff, a village three miles from Wigan, 

 there is a spring called the Burning Well, which 



