Ja-vtjaky 1, 1900.] 



KNOWLEDGE. 



21 



disseminating the sporules of a suitable insecticidal 

 fungus amongst these very destructible creatures, and 

 thereby slaying countless myriads in a very brief space 

 of time. 



The Cape mycologic flora is said to be peculiar, and 

 can scaroelv be comp-.red with any other. From the Cape 

 and Natal collections have been made by Zcyhcr Drigi 

 and others. Humidity is known to contribute largely 

 towards the copious production of fungi, and during 

 protracted droughts the regions affected thereby will 

 remain comparatively bare of fungi, but during seasons 

 of frequent rainfalls the production of a fungoid vege- 

 tation is larsrelv increased. 



BRITISH 



ORNlTHOLOCTCAt^ 



'^ 



,NQT.£S;: 



Conducted by Habby F. Withebby, f.z.s., m.b.o.d. 



The Robin and the Nightingale. — In " Cries and 

 Calls of Wild-Birds " I have compared a modified and 

 very coarse rendering of the croak of the nightingale 

 with the rattling alarm of the robin ; and I instanced 

 the croaking of two robins as illustrating a family re- 

 semblance between the cries of the two species. 

 Another, and a remarkable, instance of this has 

 recently been observed by me. 



Early in August last I heard near my garden at 

 Charlton Kings what I thought to be a nightingale 

 giving its common cry, which may be written 

 " whit-rrrr." But something in the tone of the cry 

 attracted attention, and I was astonished to see 

 what I felt positive was a robin, giving the notes. But 

 I could not see the bird's breast, and therefore could 

 not be quite sure of it. The bird soon flew away, in 

 the manner of a robin, and was seen no more. But 

 early in November I saw and heard in the hedge 

 about a quarter-mile below the railway station, a robin 

 giving the " rrrr " croak of the nightingale exactly, 

 sometimes preceding it with one or more of the ticking 

 sounds heard in the robin's rattling alarm. Mostly one 

 tick only was given. Anyone, even a good observer, hear- 

 ing the croak only, would at once have said that it 

 was uttered by a nightingale. The robin is of course 

 a near relative of the warblers, and its use of one of 

 their most typical alarm-cries is worth recording. — 

 Charles A. Witchell, Charlton Kings, Cheltenham. 



An Observational Diarii of the Uahits of Niffhtjars {Caprimulgu.t 

 Europaeus), most/i/ of a Silting Pair. Notes taken at time and on 

 Spot. By Edmund Selous. {Zoolor/isf, ?5eptembpr, 1899, pp. 388-K)H ; 

 November, 1899, pp. 486-50.5.) The very full title of this article 

 explains its object. Mr. Selous has evidently taken a vast amount 

 of pains in watching and recording most minutely the doings and 

 " sayinKs" of this pair of Nightjars from the time the eggs were laid 

 until the chicks hatched. To those who wish to be familiar with the 

 domestic arrangements of the Nightjar we recommend a periieal of 

 Mr. Selous' most original series of interviews. 



Serent Observations on the Sea fowl of the Dublin Coast. By 

 Charles J. Patten. (Irish Naturalist, December, 1899, pp. 253.256.) 

 'I'hese into^e^ting notes ehielly relate t-o the occurrence of various 

 species of waders — some of them irregular visitors to Ireland. 



itticvoscopi>. 



By John IF. Cookk, r.i,.s., F.ri.s. 



Boll covers, for protecting preparations from dust, may bo 

 made by cementing a small handle or cork to tho centre of the 

 convex side of watch glasses. 



Mr. II. F. Moore, of tho United States Fish Commission, has 

 recently published tho ri>Hnlts of his investigations on tho food 

 of herring.s. Tlio .staple diet of these tish consist of niiniito 

 organi.sms, often of microsco|)ic dimensions. Examinations of 

 tho stomachs of the fisli sliowed the food to consist largely of 

 copepods, schizo])od.s (shrimp-like forms), ampliipods (sand tieus 

 and their allies), tlie embryos of g,asteropo<ls and lamellibranchs, 

 and young lishcs, often of their own kind. ^laiiy of these 

 possess phosphorent spots, due to the prcsciico of photo-bacteria, 

 which enable the herring to follow their prey by tiight. Mr. 

 Moore has often watched the herrings at night swimming back- 

 wards and forwards in search of their prey, " apparently 

 screening the water, their every movement traced by a 

 ])hosporescont gleam evoked ]ierhaps by the very organisms 

 which they are consuming." 



The necessity for exercising great caution in the use of pork 

 as food is again brought home very forcibly to us in the last 

 report of the microscopist of the Department of Agriculture, 

 U.S.A. In the microscopal inspection for trichina;, 1,S81,:)09 

 specimens were examined, and of these 13,32,0 were found to be 

 infected. The expenses connected with this examination cost 

 the Government 11,()()9 dollars. 



Salicylic acid crystallized from alcohol gives, when mounted, 

 a beautiful combination of gold and green, with shades of 

 purple and silver points. The method of mounting is as 

 follows : — Dissolve the acid in alcohol and allow a drop of the 

 solution to fall on the slide. Apply heat for a few seconds, and 

 when cool, ring the preparation with balsam and allow it to set. 

 It may be necessary to super-impose several rings of balsam, 

 but in each ca.se the lower ring should have thoroughly set 

 before another is a[i])lied. Slightly warm a cover gla.ss and 

 place it on the ring. The cell may then be sealed with asphaltum 

 and finished according to taste. The preparation is most 

 effective as a " show " slide. 



In the same paper, Mr. MacDougall discusses the question of 

 the action of the bacteria of leguminosffi, and describes the 

 experiments of Prof. Nobbe .and Dr. Ililltner in indticing nodule 

 formation in plants by inocculation with pure cultures. To 

 make pure cultures a fresh nodule is washed carefully, and after 

 being dried in blotting paper, it is dropped for a moment into 

 corro.sive sublimate to kill any bacteria on the surface. It is 

 next washed in absolute alcohol, and cut with a scalpel that has 

 been sterilized in a Hame. A platinum needle is dip])ed into 

 the cut, and gelatine, previously prepared with a decoction of 

 leguminous shoots, is streaked with it. The bacillus radicicola, 

 being an aerobic form, requires a large surface of gelatine for 

 propagation. A pure culture is obtained in a few days. To 

 inoceulate plants with the microbe, the bacilli are transferred to 

 water, and a little of the mixture is sprinkled over the soil lu 

 which the plants are growing. 



Living diatoms survive for days when stained with methyline 

 blue .solution (one in one hundred thousand), but the vitality of 

 the cells wane from the moment the nucleus takes up the stain 



When photographing bacteria and other minute organisms, 

 the cone of light should never be reduced by stopping down. 

 Without a full sized cone of light, white diffraction lines will 

 appear around the organism. 



The use of mercury pellets is recommended to free slide 

 boxes and store cabinets from mites, jjsoci, etc., and also to 

 collect any particles of dust which may gain entrance. A few 

 small pellets of mercury, ]ilaced free in the bottom, will, by Iho 

 movement of the box or drawer, be caused to roll to and fro and 

 accomplish the desired end. 



