196 



NATURE 



[March 23, 1922 



Societies and Academies. 



London. 

 Association of Economic Biologists, February 24. — 

 Sir David Prain, president, in the chair. — J. Rennie : 

 The present position of bee-disease research. There 

 is a general similarity of symptoms in all adult bee 

 diseases. With the recognition of the parasite, 

 Nosema apis, in association with bee disease there 

 has been at the same time a failure to appreciate 

 a preponderance of cases of disease from which 

 this organism was absent. Recent work at Aber- 

 deen has shown that there are at least three 

 adult bee diseases of importance prevalent in this 

 country— all of which have hitherto been called Isle 

 of Wight Disease. Besides Nosema disease, there 

 are Acarine disease and Bee Paralysis. At the 

 present 'time Nosema disease is less common than 

 Acarine disease, but appears to be maintained to 

 some extent by the importation of foreign bees, a 

 proportion of which contain the parasite, Nosema 

 apis. Acarine disease is the more formidable malady ; 

 its causal agent is a Tarsonemid mite which breeds 

 in the thoracic tracheae and feeds on the blood of 

 the bee. An important feature in this disease, which 

 has hitherto rendered control measures difficult, is the 

 long period of infestation while the mite is being 

 established in the colony, during which time the 

 presence of the parasite is unsuspected. The 

 systematic examination for this parasite of all 

 stocks should be the first step in control. Bee 

 paralysis, described by the Swedish investigator 

 Turesson as an intoxication due to phenolic acids 

 developed in the combs and pollen by the growth 

 of various moulds, has also been recognised in 

 Great Britain. — J. Rennie : Polyhedral disease of 

 tipula species. Larvae of Tipula paludosa, the fat 

 body cells of which contain polyhedral bodies in the 

 nuclei, do not complete their development ; they die 

 before pupation. This affection, known in various 

 Lepidopterous larvae, has not hitherto been observed 

 in Diptera. The polyhedra appear to be developed 

 in association with a virus. Infection by feeding is 

 readily produced, and polyhedral bodies develop 

 within' the fat body cells in some six or seven days. 



Linnean Society, March 2. — Dr. A. Smith Wood- 

 ward, president, in the chair. — R. E. Holttum : 

 The flora of Greenland. During the summer of 192 1 

 a visit was paid to Disko Island and parts of the 

 west coast of Greenland. The most widely-spread 

 vegetation is a low heath of Empetrum nigrum 

 Cassiope telragona, etc. In specially protected 

 localities a scrub of Salix glatica was found, which 

 may reach eight feet in height, accompanied by 

 herbaceous plants of southern type. In unfavourable 

 situations there are isolated plants of resistant 

 herbaceous and woody species. The flora of the 

 whole of Greenland consists of 416 species of Vascular 

 plants, of which 18 per cent, are high arctic in type, 

 22 per cent, widely distributed, and 60 per "cent, of 

 southern type. — J. Walton : The ecology of the flora 

 of Spitsbergen. The largest number of species in 

 Spitsbergen occurs where continental conditions are 

 approached ; e.g. at the head of Klaas Billen Bay, near 

 the centre of West Spitsbergen, an area of about 5000 

 square kilometres contains 90 per cent, of the species 

 of vascular plants occurring in Spitsbergen. Three 

 vegetational zones appear : raised shingle beach, 

 alluvial land between mountain and beach, and 

 scree slopes. The development of the flora of the 

 two former can be traced to an intertidal zone which 

 resembles the salt-marsh formation of lower latitudes. 

 — Sir W. A. Herdman : Spolia Runiana — V. Summary 

 of results of investigation of the plankton of the Irish 



NO. 2734, VOL. 109] 



Sea during fifteen years. The spring phvtoplankton 

 maximum ranges from March to June, and is chiefly 

 composed of diatoms which vary greatly from year 

 to year in maximal haul, up to over 200 railUons. 

 This immense diatom curve can be resolved into an 

 earlier crest in April or May, chiefly formed of 

 Chaetoceras, and a later in June, chiefly formed of 

 Rhizosolenia. The Dinoflagellate maximum follows 

 about a month later than the diatoms, and varies 

 in our records from May to July (rarely August). 

 The Copepod maximum is later again, and ranges 

 from June to October. The largest hauls of plankton 

 are obtained, during dayhght, at a level of from 5 

 to 10 fathoms. The Irish Sea plankton contains 

 frorn 30 to 60 per cent, of Oceanic forms, the rest are 

 Neritic. Mid- winter and mid -summer are more 

 oceanic in character than the intervening months. 

 A comparatively small number of genera of Diatoms 

 and Copepoda are the dominant organisms of the 

 plankton, and these are the important food-matters 

 for the nutrition of higher animals in the sea. It is 

 probably impossible to draw numerical conclusions 

 as to the population of large sea-areas from few and 

 small samples of the plankton, for series of vertical 

 hauls taken at the same spot in rapid succession 

 show variation up to 50 per cent. The distribution 

 of plankton in the sea is not uniform, and many 

 animals such as Copepoda are present in swarms or 

 patches. As suggested by Hjort, the survival of 

 newly hatched food-fishes in early spring, upon which 

 the prosperity of future commercial fisheries may 

 depend, is possibly determined by the amount of 

 phytoplankton present at the time. 



Institute of Metals, March 8. — G. D. Bengough : 



Notes on the corrosion and protection of condenser 

 tubes. Specific recommendations are made for the 

 guidance of manufacturers of tubes and condenser 

 plants. — F. Adcock : The internal mechanism of 

 cold-work and recrystallisation in cupro-nickel. 

 Cast cupro-nickel, annealed until homogeneous, can 

 withstand considerable cold working and yet be suffi- 

 ciently hard to permit of rapid preparation for micro 

 examination. Material subjected to reductions of 

 50 per cent, and 88 per cent, by cold working was 

 examined to investigate the nature and direction 

 of certain strain planes passing through most of the 

 crystal grains of the distorted metal. Cold-worked 

 specimens annealed for fixed periods at progressively 

 higher temperatures were also examined. The effect 

 of annealing is at first the accentuation of the 

 " strain " markings, followed at higher anneaUng 

 temperatures by the appearance of new crystal 

 grains, which, if on the sites of the " strain " lines, 

 are frequently elongated in the direction of these 

 lines. The Brinell hardness of the cold -worked 

 metal did not begin to fall appreciably until the 

 annealing temperature was such that new crystal 

 grains were readily discernible under the microscope. 

 — Research Staff of the General Electric Company 

 (London) : The effect of impurities on recrystallisation 

 and grain growth. Tungsten wires were prepared 

 containing known quantities of thoria, alumina, 

 silica, lime and the alkali metal oxides, in various 

 proportions, and changes in ciystal structure on 

 annealing at 2500° were followed. The refractory 

 oxides, which ultimately segregate in the grain 

 boundaries, exert a definite resistance to grain- 

 growth. The alkali metal oxides have no influence 

 upon grain -growth, but an exaggerated growth takes 

 place on annealing tungsten containing a few tenths 

 per cent, of both a refractory oxide and an alkali 

 metal oxide. Single crystals occupying the entire , 

 cross-section of the wire, and three hundred times as 

 long as their diameter, are formed on anneaUng for a 



