40S 



KNOWLEDGE. 



October, 1911. 



into a number of zoospores, which are Uberated by the 

 dissolution of the membrane. H. GUNNEKV. 



QUARTERLY JOURXAL OF MICROSCOPICAL 



SCIHXCE.~ln the August number (\'ol. V, Part 1) of the 

 above journal there are one or two papers which may be of 

 interest to our readers. The first to which we would draw 

 attention is the interesting paper by Dr. W. E. A^>ar. devoted 

 to the Spermatogenesis of Lcpidosircn paradoxa. In the 

 course of the research most attention was paid to the method 

 by which the numerical reduction of the chromosomes takes 

 place — owing to its importance in connecting the experimental 

 l^nowledge of heredity with the structure and history of the germ 

 cells. The sections of the testes for examination were mounted 

 between two cover-slips instead of between cover-slip and slide. 

 This allowed of the nuclei being examined and drawn from 

 both sides. The advantages of this method are well shown in 

 one of the beautiful plates illustrating this paper, where two 

 figures of the same section are given, but drawn from opposite 

 sides. The other paper we would draw attention to is by 

 C. H. Martin, M,A., and Muriel Robertson, M..-\., under the 

 title of " Further Observations on the Caecal Parasites of 

 Fowls, with some reference to the Rectal Fauna of other 

 \"ertebrates." Four new species are described and figured : — 

 Chiloinastix naUinaniin. Triclioiiioitas gaUinannit. T. 

 chcrthi. Trichoiiiastix gallinciniiii. The authors say that 

 until the whole life-cycle of these animals are known the break- 

 mg-up of the complex series of forms inhabiting the caeca of 

 fowls into good species is a matter of great difficulty. The 

 Trichomonas affinities of these forms were disregarded by 

 Saville Kent (Manual of Infusoria, 18S1), who named them 

 Trypanosoma cbcrthi. The plates illustrating this paper are 

 deserving'of very high praise. They show the nuclear changes 

 that take place during di\ision and the forni.ition and develnp- 

 ment of the flagella. 



MICROSCOPY IX THE XICW •■ENCYCLOPAEDIA 

 BRITANNICA." — The article devoted to the Microscope in 

 previous editions of the '" Encyclopaedia Britannica " now 

 gives place to one by Dr. Otto Henker. The author first 

 deals with the different forms of the simple Microscope and 

 the optical theory relating to the use of a simple lens as a 

 magnifier. The Compound Instrument is dealt with more 

 fully. A short history precedes the more detailed treatment 

 of the physical theory of the instrument, the diffraction 

 problems underlying Abbe's theory of microscopic vision 

 being fully explained and illustrated. .\ short paragraph is 

 devoted to ultra-microscopy. The illuminating systems are 

 next treated and here mention is made of some old 

 methods revived for the production of dark field illumination. 

 Special attention is here given to Siedentopf's Cardinid 

 Condenser for use in this form of illumination. The 

 various methods of obtaining binocular vision with the 

 microscope are explained, and a section is devoted to 

 mechanical arrangements under which heading Micrometry 

 is dealt with. The article concludes with the methods of 

 testing the instrument. 



A special article is devoted to Microtomy by C H. I'"owler, 

 Ph.D., F"',L.S., F.Z.S., and this appears to be the only one 

 having micro-technique for its subject. In it we have the 

 theory of staining and the methods adopted for cutting 

 sections and ribbon-sections. For Photomicrography we 

 have to look under Metallography, where the method of 

 obtaining photographs of the surface of metals is given. 

 This subject has assumed such importance of late years that 

 an article devoted to its methods would have been better than 

 relegating it to the heading Metallography, which, of course, 

 is but ope of its many applications. The preparation of 

 rock-sections and their examination by means of the micro- 

 polariscope is fully and clearly explained under the heading of 

 Petrology. This account of micro-techniciue, as applied to the 

 examination of rock-sections, is excellent, .-Xttention is drawn 

 to the further refinement of microscopical method, consisting 

 in the use of strongly convergent polarized light (konoscopic 

 methodsl. This is obtained by using a wide-angled achromatic 

 condenser above the polariser and a high-power microscopic 

 objective. 



(3RNITHOLOGY. 



By Hugh Bovu Watt, M.B.O.U. 



BITTERN NESTING IN ENGLAND.~The belief 

 that the Bittern [Botaiirus sfcUaris). if given fair opportunity, 

 would resume breeding in England has, happily, been substan- 

 tiated this season. Miss E, L, Turner, when in Norfolk in 

 July, was so fortunate as to assist in finding a young bird 

 which she considered to be from four to five weeks old, and 

 the Rev. M. C. H. Bird, in the course of a joint search, 

 discovered the vacated nest. From its condition Miss Turner 

 judges that more than one inmate must have been successfully 

 reared. She gives a detailed account of her experiences in 

 Britisli Birds (September, 1911, pages 90-97), illustrated by 

 photographs of the young bird and the nest. 



The last eggs discovered in Norfolk were at L'pton, near 

 Acle, in 1,S6S, and a young bird was killed at Reedham in 

 August, 1SS6. Since then, although Bitterns ha\e not 

 infrequently appeared near their old nesting-places, they have 

 not managed to breed. It seems not much more than a 

 counsel of hope to wish that this bird may now re-establish 

 itself as a regular nesting species, however greatly this is 

 desired by bird-lovers. 



BIRDS NEW TO SCOTLAND IN 1910.— The excellent 

 and full reports on Scottish ornithology appearing annually in 

 the Annals of Scottisli Natural History are indicative of 

 the enthusiasm with which bird-study is pursued in Scotland, 

 and of the fresh discoveries and good results which reward the 

 observers. In the July number of the Annals (No. 79, pages 

 1J3-149) the first instalment of the Report for 1910 is given 

 by Misses E, V, Baxter and L. J. Rintoul, who draw attention 

 to the innnber of species and sub-species added to the Scottish 

 list during the year. These are eleven in all, and are as 

 follows : — 



L Rock-thrush {Monticola saxitilis). One adult male: 

 Pcntland .Skerries ; Orkney, 17th May. Second occur- 

 rence of species in Britain. 



2. Blyth's Reed-warbler iAcroccpluil ns di(iiuiiti>nini\. 



One: F"airlsle; September. First record for Western 

 Europe. 



3. Marsh Warbler (.4. palnstns). One; St. Kilda ; 



autumn. First time in Scotland. 



4. Temminck's Grasshopper, or the Lanceolated Warbler 



iLocustclla lanccolata). One; Pentland Skerries; 

 26th (October. F'irst record for Scotland and second 

 for Britain. 



5. American Pipit iAntlias spinolctta pcnsilvanicaK 



One : St. Kilda ; autumn. New to Britain. Only two 

 other European records. 



6. Hoary Redpoll iAcantliis horneinannii cxilipcst Fair 



Isle, no data given. F'irst record for Scotland. 



7. HolboU's Redpoll iA. linaria holhocllii). Occurred in 



some numbers in different places in eastern Scotland. 

 .s. ^'ellowshank [Totanns ttavipcs). One; F'air Isle; no 



data given. F'irst record for .Scotland. 

 The imdernanicd are continental forms of birds of which 

 there are British sub-species. 



1. Redbreast [Eritaciis riihccnia riil)cciila). One ; Isle 



of May; 2ind October. 



2. Goldcrest [Regains rcgnlns rcgidnsK Seven; Isle of 



May; between 10th September and 17th October. 



3. Great Tit [Parns major major). One: Isle of May; 



15th October, .\nother; F'air Isle; 17th No\ember. 



A'o^c-. — The first Scottish records of the Continental Song- 

 Thrush iTnrdns philomclos pliiloniclos^ and the 

 northern Willow Warbler tPhylloscopns trochilas 

 cversmanni) came both from the Isle of Ma\'. in 

 the year 1909. 

 It will be noticed that practically all these new records are 

 obtained from islands, an illustration of the importance of 

 such outposts as bird-observatories, when watched with 

 vigilance, carefulness and continuity. The records of Heligo- 

 land bv Giitke are still unri\ ailed. 



