June 9, 1887] 



NATURE 



125 



hat they ask for, or what tliey wish to call my attention to, 

 om the tone of the voice and its modulations, and this is, I 

 sume, language as regards them. On the main question, I 

 lould hold with Prof. Max Miiller from my own personal 

 :perience. H. StuaRT Wortley, 



South Kensington Museum, May 21. 



1 HAVE just noticed in a recent number of NATURE (May 12, 

 , 28) a letter from Mr. Francis Galton, in which he endeavours 

 I prove that thought without words is by no means an im- 

 jssibility. May I advance a small amount of confirmatory 

 /idence which must, I think, have come within the notice of 

 ost people ? This evidence is to be found in that peculiar state 

 " mind produced when, as we say, we have a word ' ' on the 

 p of the tongue." In this case the idea which the word, when 

 lund, will represent is most vividly present to the mind, but it 



an idea only. No language is needed to make it recognizable 

 ren though, as oftens happens, the idea may be of the most 

 )mplicated and abstract kind. Harold Picton. 



May 31. 



Diatoms in the Thames. 



In Nature, vol. xxxii. p. 223, you were good enough to 

 ublish a note from me respecting the occurrence in great pro- 

 ision of small gelatinous bodies in the water surrounding the 

 sle of Sheppey. The same conditions prevailed at about the 

 ime time last year, and in all probability will reappear at the 

 itter end of this month. 

 I have now to record that since the middle of April the sea 

 ereabout has been what fishermen call " foul " from another 

 ause. While the water has been unusually clear, in it have 

 een floating an enormous quantity of diatoms. The most 

 bundant is Coscinodiscus conciiimis, the large disks of which 

 in be seen by the naked eye in any sample of sea water dipped 

 t random. Indeed in bright sunlight they can easily be 

 bserved in the sea itself. The other forms are Rliizosolenia 

 Higem, and Eiuampia zodiacus. 



At low water the sands lying between the Thames and the 

 iledway have been coloured a rich dark brown by the diatoms 

 :ft stranded there. 

 The effect on marine life seems to have been somewhat varied, 

 lollusks appear to have thriven on the abundant food ; and as 

 irimps and whitebait have been found in abundance in their 

 sual haunts, it may be presumed that they have not been much 

 nnoyed by the diatoms. On the other hand, the flat fishes have 

 :een greatly disturbed, and could not be found on the banks 

 sually frequented. Some fishermen said they had gone right 

 svay, and would not return till the water ceased to be "foul." 

 'et this could hardly have been the case, as same have since 

 een caught on the Essex flats gorged with young cockles. 

 During the past fortnight I have examined the water at various 

 oints around Sheppey, and have invariably found the diatoms. 

 : a using the tow-net during this period, I have been struck by 

 le scarcity of animal life. Besides the diatoms, a few Nocti- 

 icse, larval Spios, and two Isopods were all that I noticed, 

 i 'hat at least some diatoms are obnoxious to fish was settled by 

 [r. Pearcey, who, in conducting tow-netting investigations in 

 iie Shetland Isles in 1884, found that in regions where large 

 pating banks of the diatom Rhizosolenia shrubsolii (Cleve) 

 pcurred animal life was almost entirely absent ; and Mr. Isaac 

 I. Thompscjn, of the Liverpool Marine Biological Society, has 

 bcorded a somewhat similar experience in 1885 off the North 

 Vales coast. 



! : It will be interesting to ascertain from which direction these 

 iuntless myriads of diatoms have reached the Thames, and 

 ithin what limits they have been found. To this end I invite 

 bservers round the British coast to examine the water in their 

 ;spective localities, and to publish the result. 

 In water obtained from the coast of Holland I could not 

 elect a single diatom. 



I have reason lo believe that an abundant influx of the same 

 laracter has taken place in previous years, but coming at a 

 me of year when the weather is not often favourable for con- 

 iicting marine observations, the facts have escaped scientific 

 btice. W. H. Shrubsole. 



Sheemess-on-Sea. 



P.S. — The above was written about a fortnight ago, and now 

 /lay i8) the gelatinous masses are beginning lo appear. — 

 " H. S. 



The Structure of the Nostochinese. 



I WAS glad to see in Nature, vol. xxxv. p. 594, a suitable 

 notice of Prof. Borzi's very interesting paper on the above sub- 

 ject. So far as regards the discovery of the continuity of the 

 protoplasm in this group of plants, I should like to be allowed 

 to state that in my paper "On the Constitution of the Cell- wall 

 and Middle Lamella," read February 10, 1884, and published-in 

 the Proceedings of the Cambridge Philosophical Society, vol. v. 

 part ii., I drew attention to the fact that in NoUoc I had ob- 

 served a continuity of the protoplasm between adjacent cells. 

 But I simply stated the bare fact, and my note was therefore 

 even more pronouncedly " una brevissima comunicazione " than 

 that of Wille's on Stigonema, to which Prof. Borzi refers. 



Clare College, Cambridge. WALTER Gardiner. 



Curious Phenomenon in Capillarity. 



For some years past I have been in the habit, when putting 

 up at obscure hotels and remote ' ' dak bungalows " during 

 inspection tours, of putting a few drops of the cheap disinfectant 

 known as "Little's soluble phenyle " into my tub before 

 bathing. The bulk of the liquid, when dropped into clear 

 water, diffuses downwards as a milky white emulsion, giving 

 beautiful imitations of inverted cumulus clouds ; but a small 

 portion of it, perhaps some oily impurity in the mixture (which 

 is sold under the trade mark CgHg, and should therefore pre- 

 sumably be a definite compound), instantly spreads out over the 

 surface as a drop of oil would do, and then, strange to say, after 

 the lapse of about half a second, and usually before the film has 

 extended more than half-way across the tub, it again contracts. 

 The contraction of the film proceeds until it is only two or three 

 inches in diameter, after which its size appears to remain 

 stationary ; but about this time the distinct outline of the film 

 usually disappears, owing to the gradual mixing of its substance 

 with the water below — a circumstance which leads me to believe 

 that the film is not caused by an oily impurity, but by a part of 

 the " phenyle " itself, which possesses the property of emulsifying 

 with water. Temperature seems to have no effect on the pheno- 

 menon, beyond perhaps modifying the rate at which the film 

 expands and contracts, the effect being apparently exactly the 

 same whether the liquid be added to a cold bath at 60° or to a 

 hot one at 100° F. 



Have any of your readers observed this phenomenon, or can 

 anyone give a satisfactory explanation of it? According to the 

 usual theory of the subject, the surface-tension of water in con- 

 tact with air is greater than the tension of a phenyle -air surface 

 plus that of a phenyle-water surface, and hence the film of 

 phenyle spreads like one of oil. But after a time, when the 

 phenyle gets partially emulsified, the sum of the tensions of the 

 two phenyle surfaces must be greater than that of the water 

 surface to make the film contract, and apparently after some 

 further time a condition of equilibrium is established. Is there 

 anything in the process of emulsification, or dividing a liquid up 

 into minute globules suspended in another liquid, that will 

 account for these changes of surface-tension ? 



Naini Tal, India, May 2. S. A, HiLL. 



Sense of Taste or Smell in Leeches. 



I HAVE recently observed very well marked phenomena, 

 similar to those described by Dr. C. O. Whitman {Quart. Journ. 

 Micro. Science, vol. xxvi. new series, p. 409). I picked up 

 with my fingers a stone from the soft muddy bottom of a shallow, 

 torpid stream. Returning to the same spot a few minutes 

 afterwards, I noticed a number of leeches (apparently Hirudo 

 sp.) swimming near the spot. On the following day, suspecting 

 that they had "smelt" or "tasted" my hind in the water, I 

 first stirred the surface of the mud with a stick, but no leeches 

 appeared; after the water was clear again I "washed my 

 hands " in the water without disturbing the mud, and very soon 

 a number of leeches came up and swam about. The soft mud 

 in which they live is about a foot deep, and although the dis- 

 turbance of the surface mud with a stick was not sufficient to 

 bring them out, the "smell" or "taste" of my hands seems to 

 have spread down and extended over an area of more than a yard. 



Last year I had an opportunity on these hills of observmg the 

 very keen "scent" of the land leeches, who will come towards 

 one's self or one's horse from the banks on either side of even a 

 wide road. A. G. Bourne. 



Ootacamund, Nilgiris, April II. 



