Mav, 191. 



KNOWLEDGE 



101 



endosperm ; in this case it appears in section twisted 

 round, like a coilednp caterpillar, and we refer our speci- 

 iiKMi to the i^roiip Canipylospcrmeae. The most familiar 



Figure 220. Cross Section of the Stem of Sunflower. 



character of these "seeds" is their strong smell, due to 

 the oil contained in the vittae, in most species. The well- 

 known CN'mene phenol carvacrol, which can be made by 

 boiling camphor with iodine, owes its name to Cariini 

 Ciiriii. carvol (caruoU having been the term applied to the 

 oxidised constituent of carraway oil, carvene (caruene) being 

 the hydrocarbon. Pliny (N.H. 23 : 8S) says that oleum 

 caryiiiiini is good for headache, so that it is possible that a 

 substance allied to thymol was used for similar purposes in 

 classical times; marjoram is used to anaesthetise lulus in 

 Aen. I, 692. Pliny indeed connects his oleum caryinunt with 

 iiiix jiiglati!;. but this is probably because he connects it 

 wrongly with caryon, " a nut,'" the real word being caron and 

 its adjective caroinon, whence wine and nuts have wrongfully 

 attached themselves to the carraway throughout its literary 

 history. Many of the terpenes seem to have been known to 

 the ancients, and if we could get them correctly identified we 

 might think better of the empiric medications of those distant 

 days. The specific name Canii, given by Linnaeus, seems to 

 be a latinisation of the vernacular name as still used in several 

 European countries : and this itself is derived 

 from Pliny's term, the mistaken orthography 

 being shared by no less a person than Galen. 

 To return to the twentieth century : these fruits, 

 when duly fi.xed, are not difficult to sectionise, 

 if care be taken to bring them to the right 

 consistency; perhaps the best way is to embed 

 them in parathn, and cut them like ordinary histo- 

 logical sections, since in this case the block 

 remains as a source of further specimens if 

 such should be desired. The photographs were 

 taken with the Zeiss thirty-five millimetres pro- 

 jection lens, illuminated with the Kohler system 

 and the back of the aplanatic condenser. 



E. W. BOWELL. 



gUEKETT MICROSCOPIC.-^L CLUB. — 

 March 26th. Professor A. Dendy, D.Sc. F.R,S., 

 President, in the chair. Mr. E. M. Nelson, 

 F.R.M.S., exhibited '"An Aplanatic Spot Lens." 

 This, recently made by Messrs. Baker from his 

 calculations, focusses parallel rays directly upon 

 the object. Its N.A. is 1-3 and its focus eight 

 millimetres. It is a single lens with a convex 

 reflecting surface, which is also' a concave re- 

 fracting surface, the latter introduced to neutralise 

 the aberration of the concave mirror. 



Mr. Nelson also described "An Improved Chromatic 

 Condenser." Owing to the many faults of the ordinary 

 .Abbe condenser it was suggested that it would be well to 

 have a simple form of non-achromatic dark-ground 

 illuminator that would be capable of doing real 

 serviceable work, and also for ordinary work a 

 cheap narrow-angled chromatic condenser with 

 spherical aberration at a minimum. The first had 

 already been done and was exhibited and des- 

 cribed at the meeting of the Club in March, 1911. 

 The new condenser now exhibited is a non-achro- 

 matic triple of 0-65 N.A. and of minimum 

 aberration. It is composed of two menisci and 

 one bi-convex. 



A third paper by Mr. Nelson on "The Rousselet 

 Compressor " was also read, 



Mr, E^arland brought before the Club's notice 

 a very important paper on "The Las>eiiae of the 

 South-West Pacific," contributed to the Club's 

 Journal by Mr, Henry Sidebottom, 



Mr, C, F. Rousselet, F,R,M,S,, made a com- 

 munication on Notholca triartliroides Skorikow, 

 Cathypna brachydcictyla Stenroos, and a new 

 HrachioiiHs from Devil's Lake, North Dakota, 

 L'.S,.A, The new species was B. spatiosiis, foimd 

 in plankton material collected by Professor K. T, 

 Young, in July, 1910, In shape and appearance 

 the nearest forms are B. latissimits and B. 

 longipes of Schmarda. 

 Mr. D. Bryce read a paper on three new species of Callidinn. 

 These were C. nana, C. concinna, and C. decora. 



Mr. A. E. Conrady, F,R,M.S., read a paper on the resolving 

 power obtainable with dark-ground illuminators. The full 

 resolving power of an objective was only obtained when the 

 dark-ground illuminator had three times the numerical 

 aperture of the objective obtainable, or, stated in another 

 way, the resolving power was equal to one-fourth that of 

 the objective plus one-fourth that of the condenser. No 

 higher resolving power can be obtained with dark-ground 

 than will be given with an objective having a N.A. of 0-47. 



Mr. A. A. C. Eliot Merlin. F.R.M.S., sent a note on a 

 photograph of the secondary structure of Xavictila Smithii. 

 The photograph showed the structure described at the meet- 

 ing of the Club, October ISth, 1907, and, the writer thought, 

 left no reasonable doubt as to the objective reality of the 

 markings observed. The photograph was taken at a direct 

 magnification of X2,900 with an apo. ath inch of 1-42 N.A. 

 and an axial cone of 0-5 N.A. 



Dr. T. W. Butcher sent a series of ten photomicrographs of 



Figure 221. Section of the Thorax of a young Rat. 



