HARDWICKE'S SCIENCE-GOSSIP. 



233 



aquarium. I have twenty strong healthy fish from 

 ova deposited in my tank. The young fry are not 

 more than a month old, and vary from three-quarters 

 to an inch in length. Already I feed them with 

 quantities of gnat larvse every day, and have not 

 had a single death amongst them yet. Unfor- 

 tunately the parents were removed from the aqua- 

 rium too soon, or I might have had a great many 

 more, having obtained nearly a tablespoonful .of 

 spawn from the female afterwards, which I tried to 

 vivify with the male by mixiug the milt with it, 

 but failed. It did not show any sign of hatching 

 excepting a cloudy nucleus. — IF. Elliott. 



BOTANY. 



Notes from the British Association Meet- 

 ing.— There was a striking absence of botanists 

 from this year's meeting, although Dr. Hooker, 

 Mr. George Bentham, Prof. Cohn, Prof. Balfour, 

 Prof. MacNab, and others were present. We have 

 seldom seen botanical papers in such weak force. 

 Mr. A. R. Wallace's remarks on the relation be- 

 tween the colours and perfumes of flowers and 

 insects added new light to this important subject, 

 for he showed that certain sun-birds and humming- 

 birds fulfilled botanical functions in this respect. 

 One of the most promising young botanists of the 

 present day, Dr. J. B. Balfour (son of the venerable 

 Professor of that name), read a series of notes on 

 " Mascarene Species of Pandani." The Mascarene 

 Islands are in the Indian Ocean, some distance from 

 the Mauritius, and these islands are characterized 

 by very peculiar genera of plants. Of twenty-two 

 species of Pandanus found in the islands, twenty 

 were peculiar to them. Mr. George Bentham, 

 speaking on this paper, said the Pandanus was a 

 plant in which they had very great interest, because 

 it was known to be one of the Pandani representa- 

 tive of some of the oldest types of vegetation, and, 

 like all old types of vegetation, it was distinguished 

 by endemic species, confined generally to very 

 limited areas of territory. Very little was known 

 about the plant ; indeed, a great number of the 

 species were almost unknown to botanists. Another 

 important paper was one by Prof. Cohn, well known 

 to English botanists, not only for his paper on 

 Volvox globator, but for his general researches in 

 Algae. The Professor, in good English, discoursed 

 on some experiments on the formation and mode of 

 growth of artificial silica-cells, and performed some 

 of them before the company, in order to throw 

 light on the structure of diatoms, &c. Prof. 

 Burdon-Sanderson gave us an account of further 

 researches on the leaves of the Ply-trap (Dionea 

 muscipula). He exhibited a fine specimen of the 

 Ply-trap, and described the formation of the plant, 

 how the leaves closed when a fly lighted on them, 



and how the insect was held by the hairs which 

 crossed each other in triangular form, and which 

 were so jointed that, when the leaves closed, they 

 were not broken. He next gave the result of ex- 

 periments made on the plant with an electrical 

 apparatus. At the Bradford meeting he had brought 

 forward certain new facts relating to the electrical 

 changes which took place in the leaf of the Ply- 

 trap in consequence of mechanical irritation. These 

 changes were of such a nature as to show, first, that 

 the leaf, when in the normal state, was electro- 

 motive; and, secondly, that when excited, either 

 mechanically or electrically, it became the seat of 

 electrical changes of a very remarkable kind. He 

 drew a most interesting parallel, which he then, and 

 still, thought justifiable between these changes and 

 those which occurred in animal muscle, and in the 

 excitable tissues of animals in the process of exci- 

 tation. 



Destruction of Rare Plants. — In the hope 

 that others will take up the note, and sound an 

 alarm far louder than I can do, I wish to direct the 

 attention of all real botanists, all true lovers of the 

 science, to the pitiless destruction that is every- 

 where going on among our rarer indigenous plants. 

 It is not necessary for me to enter into full details, 

 for to many the fact will be only too patent ; but I 

 will simply speak of what I personally can vouch 

 for. Only a few days ago a relative of mine went 

 to pay a visit in one of the secluded parts of 

 Surrey, with the hope of making some valuable 

 additions to his herbarium, as the locality is famous ; 

 but on inquiring of a botanical friend who resides 

 near, he was told, that on account of the rapacity of 

 collectors, they had nearly all disappeared ! Last 

 year I was at Cheddar, a place where several rather 

 uncommon ferns are to be found, and I was told 

 that in the season large quantities are grubbed up, 

 and sent off by railway. The rage for ferns is now 

 so universal that, if it long continues, the rarer and 

 prettier kinds will almost disappear. I was in- 

 formed a short time ago by a gentleman who knows 

 what is going on in the botanical world, that some 

 one has a commission to gather five hundred speci- 

 mens of each of our rare plants to send to America ! 

 It would be difficult, in such a case, for many of 

 our rarities to escape complete extirpation. What 

 is , to be done ? Two things may at least be 

 observed ; one is, whoever is collecting specimens, 

 ought to be particularly careful not to gather more 

 than is necessary, not to uproot a plant, and, if 

 possible, to leave ripe seeds. Many do great harm 

 from thoughtlessness rather than greediness. Also, 

 one must be most careful not to divulge the locality 

 of any rare plant without knowing something of the 

 person who applies, and in return a promise of 

 absolute secrecy should be required. I am in pos- 

 session of the knowledge of several localities of 



