HARDWICKE'S SCIENCE-GOSSIP. 



91 



development. No couuectiou can be traced between 

 the number of spores present in the air and the 

 occurrence of diarrhoea, dysentery, cholera, ague, &c. 

 It will be seen, from the scope of the book, that 

 its contents are of a most important character, as 

 bearing on the vexed question of spontaneous 

 generation. 



BOTANY. 



Seaside Shrubs. — As considerable interest is 

 now being taken on this subject, it may be as well 

 to draw attention to two shrubs coming under the 

 above denomination ; viz., the Atriplex halimus 

 and Atriplex portulacoides. The former is a tall 

 evergreen shrub, growing on sandy shores in the 

 south of France, five or more feet high. Loudon, 

 in the "Encyclopaedia of Plants," says: "In this 

 country [England] its silver-coloured foliage adds 

 to the variety of our shrubberies." At Marseilles, 

 in the public promenade above the town, an ele- 

 vated exposed spot, it forms very thick hedge- 

 fences, as also at one of the railway-stations, some 

 miles inland, on the Paris line. Some years back 

 I saw a plant of it in Mr. Spary's nursery at 

 Brighton, which I rather think came from a nursery 

 at Ventnor, in the Isle of Wight. There is every 

 reason to suppose it would bear the cutting winds 

 on the Brighton seashores. The Atriplex por- 

 tulacoides, or Sea Purslane, is a dwarf shrubby 

 British plant, growing on muddy, clayey, or poor 

 gravelly seashores in England and Ireland, two 

 or more feet high, with small yellowish flowers. 

 No doubt there are other shrubs peculiarly adapted 

 to our seacoasts, which it is hoped those who 

 have tested their fitness will bring to notice. Re- 

 ferring to the Hippophae rhanmoides, mentioned in 

 a former number of Science-Gossip, it may be 

 as well to state that an easy way to secure the two 

 sexes, in order to obtain the beautiful berries, 

 which are very abundant in bunches like the holly, 

 is by layers or cuttings of the roots of shrubs of 

 both sexes. They will grow in common soil. Mr. 

 Balchin has one in his nursery at Hove, but which 

 produces no berries, for the want of the two sexes. 

 —T. B. W., Brighton. 



Sudden Appearances of Plants. — Macaulay, 

 speaking of the battle of Landen, says : " The 

 next summer the soil, fertilized by twenty thousand 

 corpses, broke forth into millions of poppies. The 

 traveller who, on the road from Saint Tron to 

 Tirlemont, saw that vast sheet of rich scarlet 

 spreading from Landen to Neerwinden, could 

 hardly help fancying that the figurative prediction 

 of the Hebrew prophet was literally accomplished, 

 that the earth was disclosing her blood, and re- 

 fusing to cover her slain." (Hist. Eag., vol. iv. 

 chap, i.) Is there any other instance of this on 



record, and is anything known of the species? 

 These occurrences, like the appearing of Sisym- 

 briuni Iris on the ruins of burnt London, are very 

 curious.— <7b/«« E. Eobsoti. 



The London Catalogue of Plants. — On look- 

 ing over the sixth edition of the " London Cata- 

 logue," and noting the census-figures which follow 

 the names of the species, I remarked some records 

 which seemed unaccountable. Hypericum humifusvm 

 is credited only with being at home in eight 

 counties. Is this a printer's error ? I have long 

 considered this as one of our commonest plants. 

 In Ireland it is so ; it occurs with us from north to 

 south, and most likely in all, or nearly all, our 

 thirty-two counties. Again, surely Littorella lacus- 

 tris is not so rare that it can be found in only nine 

 counties. In this island it is reported from most 

 of our districts, and I am sure it occurs in twice 

 nine Irish counties. And again, why is it that a 

 query follows the name of Cicuta virosa ? a well- 

 known and easily distinguished plant, and one of 

 the most unlikely to be introduced artificially. 

 Perhaps some correspondent may be able to throw 

 more light on these points. The prevalence of 

 plants such as the above should not, at the present 

 day, be at all obscure. — S. A. Stewart, Belfast. 



Water in Plants.— At a recent meeting of the 

 Royal Irish Academy, Prof. M'Nab read a report 

 on some researches into the physiology of plants. 

 These experiments were, first, a series to determine 

 the amount of water transpired by leaves ; and, 

 secondly, the ascent of water in the stem. The 

 plants selected for both series of experiments were 

 the cherry-laurel, the common privet, and the 

 common elm. It would be impossible to condense 

 the large series of experiments made by the author. 

 One series, to deteraiine the amount of water 

 transpired by leaves, made on August 7, 1S73, 

 showed that, with very nearly the same exposure, 

 and under the same conditions, the cherry-laurel 

 lost, of water, 51"81 per cent, of the weight of the 

 branch employed ; the privet, 2678 ; theelm, 65"6i. 

 Very many experiments were made to determine 

 the actual rate at which fluid ascends in the stem. 

 In Sach's experiment on this subject he fixed the 

 rate to be 9 in. per hour. In Dr. M'Nab's first 

 experiments he obtained a rate of 24 in. per hour. 

 The present series of experiments were made on 

 the same species of plants mentioned above. In 

 the privet the rate was 6 in. per hour ; in the elm 

 the rate was 15'6 in. per hour. But in both plants 

 the leaves and stem soon became flaccid, and the 

 experiments were not completely satisfactory. In 

 the cherry-laurel the rate in one experiment was 

 24 in. [per hour; in a second, 13-2 in. per hour; 

 and in a third, 18'6in. per hour. The author also 

 recorded a large series of experiments : 1. As to 

 the rapidity of the ascent of fluid in stems when in 



