November 26, 1908J 



NATURE 



99 



Like Prof. Johnson, I have found no difficulty in 

 j^erniinaling them in potato-juice at the ordinary labora- 

 tory ti-niperaturc. At the commencement of August they 

 had liberated their contents within four days in a hanging- 

 drop culture. I was not so fortunate as to observe the 

 actual escape of the zoospores, but this stage seems to 

 be followed very rapidly by the amoeboid stage, in which 

 condition the organism moves about very actively for some 

 days. In the hanging drop it then becomes passive, with- 

 drawing its pseudopodia and assuming a spherical shape. 



In both the ciliate and the amoeboid condition it must 

 be very sensitive to fungicides, and it is therefore 

 important to ascertain at what period this susceptible stage 

 i- reached in nature, as this will determine the best time 

 for the application of gas lime or other dressing to the 

 soil. Now that so many observers are directing their 

 .•mention to this fungus, it is to be hoped that we shall 

 ~oon discover a method of checking the further advance 

 . f this destructive parasite. F. E. Wkiss. 



The University, Manchester, November 21. 



Mercury Bubbles. 



I iiAVF on several occasions noticed the beautiful bubbles 

 described by Mr. Wright and Sir William Crookes (pp. S 

 and 37). On each occasion I was purifying mercury in 

 the following way. I half filled a rather large Woulffe's 

 bottle with mercury and poured on to it weak nitric acid. 

 Then, in order to keep the w-hole in a state of agitation, 

 I carried a tube through one neck to the bottom of the 

 bottle and attached a short tube to the other neck con- 

 nected with a filter pump, so that air was continuously 

 drawn through the two liquids. I have never noticed 

 bubbles for the first hour or two, but afterwards they are 

 formed continuously, and float for a second or so on the 

 top of the acid before bursting. Some were certainly quite 

 22 mm. in diameter. From their delay in appearing I 

 gather either that they are only formed in mercury which 

 is fairly pure, or that the nitric acid has to be fairly well 

 saturated with metal. A. T. Hare. 



Xovember 23. 



With reference to Mr. J. G. Ernest Wright's letter in 

 Nature of November 5, I may be permitted to mention 

 that under the above heading I published a few observa- 

 tions in Nature of July 2, 1903. Like Mr. W'right, I 

 made an approximate estimate of the thickness of the 

 mercurial pellicle, but the bubbles which were produced in 

 Mr. Wright's experiment seem to have had a slightly 

 greater diameter than any of those which I observed. 



Henry H. Dixon. 



School of Botany, Trinity College, Dublin. 



An Alga growing on Fiah. 



In Nature of April iS, 1907, vol. Ixxv., p. 599, it Is noticed 

 that Mr. A. D. Hardy found a cholorophyte, Myxonema 

 tcnue, ordinarily an inhabitant of rapid streams, also grow- 

 ing luxuriantly on some goldfish in a small pond, thus 

 obtaining water friction necessary to its own well-being. 



To some_ of your readers it might prove of interest to 

 record a similar occurrence in Japan. On October 11, 

 1902, while I was rambling about the Asso marsh, not far 

 from this town, my eye was accidentally caught by a small 

 fry of medaka (lit.', eyes-jutting, Haplochiltis latipes, 

 Schleg.), a fish proverbial for its diminutiveness. In a 

 shallow bog-pool, only some 2-4 feet across, they looked 

 very unhealthy, and were swimming in an unsteady, fidgety 

 manner, infested with what appeared to be Sapr'olegnia, 

 but greenish in hue. On a closer examination, every 

 one of them turned out to have under or beside its 

 abdomen a horny protuberance giving rise to delicate tufts 

 of an alga up to i cm. long. This discovery I made 

 mention of in a letter sent some time after to Prof. G. S. 

 West, then at Cirencester. This plantlet, I have no doubt 

 belongs to the genus My.xonema, but the imperfection of 

 NO. 2039, VOL. 79] 



my microscope, as well as the want of reference books, 

 prevents me from ascertaining what species it really is. 



By the accompanying parcel post 1 am sending you five 

 mvdaka-Rsh with the algal growth in situ, and two slides 

 with the latter ; also one slide with a large, broadly shuttle- 

 shaped and much constricted desmid found singly suspended 

 among the Myxonema, in the hope that some phycologist 

 will kindly identify them for me. 



KuMAGusu Minakata. 



Tanabe, Kii, Japan, September 20. 



The alga attached to the medaJia fish is Myxonema 

 tcnue, Rabenh. The desmid is a species of Euastrum, 

 too imperfect to determine specifically. A few fragments 

 of a diatom belonging to the genus Gomphonema are also 

 present. Geo. Massee. 



A Disclaimer. 



I wish to make a disclaimer of responsibility with refer- 

 ence to the journal Ion, on the ever of the first number 

 of which my name figures in tl e capacity of an editor. 

 It is true that at one time, ac'.ng on certain representa- 

 tions, I accepted an invif .tion to superintend the 

 department of the journal dealing with radio-activity, 

 as referred to in the concluding paragraph of the 

 editorial on p. i of the first number. Neither the journal 

 itself, nor its cover, however, were submitted to me for 

 my sanction and approval before publication. The appear- 

 ance of my name on the cover in the capacity of an editor 

 has not been authorised by me, and I accept no responsi- 

 bility with regard either to the editing or publishing of 

 the journal. 



With reference to the department of the journal dealing 

 with radio-activity, I would point out that the first number 

 of the journal contains several articles and reports deal- 

 ing with the subject of radio-activity, but wi.th the excep- 

 tion of two articles contributed by myself and one report, 

 proofs of which passed through my hands, these articles 

 and reports were not seen by me before publication. The 

 first intimation I had that they were to appear was derived 

 from the adverrisement of the journal and its contents in 

 Nature of November 12, p. xxi. I therefore do not accept 

 any responsibility for that section of the journal I am 

 stated to have the care of. Finally, I wish to sav I have 

 now withdrawn from all connection with the journal. 



Frederick Soddv. 



Leonid Meteors. 



The nights of November 13-15 appear to have been 

 generally overcast, and to ha.ve furnished no opportunities 

 for watching the display of meteors. But November 16 

 was clear at some places, and Mr. Ellison Hawks, of 

 Leeds, counted eighty-seven meteors between loh. and i4h., 

 of which twenty-six .appeared to be certainly Leonids, while 

 many others pursued nearly same paths, and probably 

 belonged to same stream. Large meteors were recorded 

 at I2h. 26m. and I3h. 12m. shooting from Taurus and 

 Aries towards the planet Saturn. 



At Whitby an observer noticed several conspicuous 

 meteors in the morning hours of November 17. At 

 6.32 a.m. there was a splendid one descending almost 

 vertically through Orion from the direction of Leo, and 

 there was no doubt that the great November stream re- 

 turned, though perhaps not richly as in some years nearer 

 the perihelion returns of the parent comet. It is to be 

 hoped that other observers will send their reports of the 

 shower. 



The night following Monday, November 16, when the 

 Leonid meteors were seen at Leeds and Whitby as de- 

 scribed, was decidedly late for the display. The present 

 year being leap year, it is probable that the shower was 

 at its best on the mornings of November 15 and i6, but 

 no accounts of its appearance at those times have reached 

 me owing to the overcast and starless condition of the 

 visible firmament reported by various observers. 



W. F. Denning. 



