SCIENCE. GOSSIP. 



2 77 



planations, which, it was hoped, could be put into 

 a form suitable for publication in the journal. A 

 sliding microtome by Eeichert was exhibited by 

 Mr. C. Lees Curties, and described by the Secretary. 

 This machine was on the " Thoma "" model, 

 with mechanical adjustments to every part, 

 even to the tilting of the knife. The micrometer 

 screw was reversible, thus obviating tedious un 

 winding. The instrument was very moderate in 

 price. Mr. D. J. Scourfield, F.E.M.S., read a Paper 

 on " The Ephippia of the Lyceid Entomostraca." 

 The author originally intended to wait for sufficient 

 material for a more comprehensive Paper, but in 

 view of the wideness of the subject preferred to 

 deal with a part which had been fairly well worked 

 at. He described the principal features of the 

 formation and casting of these particular ephippia; 

 the curious membrane around the egg, the thicken- 

 ing of the posterior margins of the valves, the 

 growth of the line of cells across the valve where 

 the separation eventually takes place, and other 

 apparently constant accompaniments. The author 

 then showed the great variations in the sizes and 

 shapes of the parts of the valves which were cast 

 by different species, and stated his belief that such 

 variations were of value in determining species. 

 The real uses of the marginal thickenings of the 

 valves and the membrane surrounding the egg 

 were suggested. A Paper, by Mr. E. M. Nelson, 

 F.R.M.S., " On the Black and White Dot," was read 

 by the Secretary. The author asked indulgence 

 for what might appear a puerile subject, but 

 claimed that a proper understanding of the forma- 

 tion of the diatomic images must be the prelude 

 to the acceptance of any theory of microscopic 

 vision. He then proceeded to criticise the Papers 

 read earlier in the year by Mr. Rheinberg and Mr. 

 Stokes, rejecting the " special " theory of the 

 formation of the " black and white dots " made 

 out by the former, and, though agreeing with much 

 that the latter had stated, putting forward evidence 

 which he believed to be in opposition to some of 

 Mr. Stokes's conclusions. 



Abnormal Secondary Thickening in Climb- 

 ing Plants. — In its summary of botany at the 

 last meeting of the British Association, " Nature " 

 mentions a paper by Miss A. M. Clark in which 

 the author describes the process of formation of 

 the abnormal secondary thickening in Kendriokia 

 nvallieri, a tropical epiphytic climbing shrub. The 

 anatomy of the young stem is typical of the family 

 Melastomaceae. At an early stage numerous small 

 patches and several large wedge-shaped areas of 

 thin-walled unlignified wood-parenchyma are cut 

 off from the inner side of the completely circular 

 cambium ring. Tylosis is of frequent occurrence, 

 and the tylosed cells may develop into sclerotic 

 cells inside the vessels and tracheids. At a later 

 stage the unlignified wood-parenchyma cells, at the 

 central margin of the wedge area, take upon them- 

 selves new growth accompanied by cell- division. 

 The product of this new growth proceeds to split 

 the axial woody ring into a number of portions, 

 with subsequent destruction of the identity of the 

 wood elements. Later, the quiescent cambium, 

 lying between the original internal phloem and 

 the axial woody ring, takes upon itself new growth, 

 and proceeds to lay down xylem on the one side 

 and phloem on the other. Some of our readers 

 will remember the discussion in Science-Gossip 

 {ante, p. 56, and vol. vii. pp. 372-4) on the abormal 

 growth of the stems of Brazilian Lianes. 



Method for Rearing Amoebae.— A con- 

 tributor to the American "Journal of Applied 

 Microscopy " gives the following simple method 

 of securing Amoebae. A nutrient medium is made 

 by boiling a lot of dead leaves. As soon as cool,, 

 both liquid and leaves are placed in an ordinary 

 battery jar, and a lot of unboiled leaves, and 

 enough water added to stand about one inch above 

 the leaves. In two or three clays a scum will form, 

 and in from five to ten days, depending upon the 

 temperature of the room, Amoebae will be found 

 in the scum in large numbers, but somewhat small. 



The Arrangement op Cilia on Paramecium. 

 — The same journal contains a note on staining the 

 cilia of Paramecium, which, in common with those 

 of many others of the Infusoria, are so fine and so- 

 closely set as to make it difficult to determine their 

 exact arrangement even by the most careful 

 focussing. A drop of Loeffler's alkaline methylene- 

 blue is mixed with a drop of water, in which the 

 animalcules are swimming on the slide, and the 

 cover-glass placed in position. Intra vitam stain- 

 ing takes place in many of the individuals ; but 

 they soon die, and the cuticle separates more or 

 less completely from the cytoplasm and forms a 

 halo round the deeply stained body. The perfora- 

 tions in the cuticle are thus brought very distinctly 

 into view and the plan of arrangement of the cilia 

 revealed. The stain is prepared as follows : Add 

 30 c.c. of a concentrated alcoholic (95 per cent.}, 

 solution of methylene-blue to 100 c.c. of a -0001 

 solution of caustic potash. The caustic potash, 

 solution may be prepared by adding 1 c.c. of a 

 1 per cent, solution of potash to 100 c.c. of distilled' 

 water. 



New Objectives by Otto Himmler. — By the 

 courtesy of Messrs. W. Watson & Sons, of High. 

 Holborn, London, we have recently had an oppor- 

 tunity of examining two objectives by a compara- 

 tively new maker, Mr. Otto Himmler, of 9 Branden- 

 burgstrasse, Berlin, that deserve more than passing- 

 notice. They were styled semi-apochromats, whichi 

 implies only, we presume, that in them the newer 

 Jena glasses have been used. Their corrections- 

 were exceptionally good, and showed once more 

 how near the best and newest achromatic lenses 

 come to the more costly apochromats. These 

 particular lenses were |-inch and J^-inch oil im- 

 mersions, with N.A. 1-3. Both were excellent, but 

 the ^-inch was really one of the finest achromatic- 

 objectives we have seen, possessing brilliant 

 definition, whilst the price was only £3 5s., and! 

 £4 10s. for the ^-inch. 



Immersion Oil in Collapsible Tubes. — The 

 same writer alludes to the disadvantages attendant, 

 upon the use of the ordinary bottle for immersion, 

 oil, which it is impossible to keep clean, and which 

 allows the oil to thicken, turn yellow, and. 

 become turbid through exposure to light and air,, 

 thus altering its refractive index. In consequence 

 the use of collapsible tubes is suggested, similar to- 

 the tubes which are used for holding moist water- 

 colour and oil paints. It is stated that this form of 

 tube has been used to contain Canada balsam with 

 satisfactory results, and the writer referred to. 

 determined to try how such tubes would do for 

 immersion oil, although he was warned that the 

 metal might have some deleterious effect upon the- 

 optical properties of the oil. After a year's ex- 

 perience he is able to state that the tubes have- 

 proved to be quite free from the faults whichi 



