October 17, 1912] 



NAl URE 



'97 



sky-line, while the latter stands out sharply silhouetted 

 against the same. 



The bright coloration of most Hemiptera is due to 

 a fattv tissue known as pseudovitellus, and this tissue 

 invades the developing egg at an early stage of 

 maturation. Its significance has been variously inter- 

 preted, but only quite recently has its true function 

 been discovered. Thanks to Sulc and Pierantoni, it 

 is now known to be the habitat and to provide the 

 food of multitudes of symbiotic organisms, probably 

 veasts. Every Aphis, every Psyllid, is a synthesis of 

 two organisms, one the insect and the other the sym- 

 biont. Dr. Buchner, '"Studien an intracellularen Sym- 

 bionten " (part i., .4j'c/u''y /. Protistenkunde, vol. xxvi., 

 1912), has taken up the detailed study of the range 

 and nature of this form of symbiosis, and he gives 

 a verv interesting and well-illustrated account of his 

 researches. Beginning with certain CoccidsE, in which 

 the pseudovitellar cells may be present or absent (facul- 

 tative mvcetocytes), he proceeds to describe the definite 

 organ (mycetom) which they form in Aphids and 

 others. Thev may be infected by one kind of sym- 

 biont, bv two kinds rigidly kept from commingling, 

 or even (Psyllidse) by three kinds. Similar symbiotic 

 organisms are not limited to Hemiptera, and indica- 

 tions are given that they occur in cockroaches, beetles, 

 Hvmenoptera, and Lepidoptera. The organisms are 

 carefully described, and the whole subject is one that 

 deserves the fullest attention from botanists, and 

 especially from mycologists. The relations between 

 the insect and the svmbionts are still in need of 

 elucidation. 



We have received from Messrs. Gallenkamp and 

 Co., Ltd., Sun Street, Finsburv Square, E.C., a copy 

 of their new catalogue of apparatus for botanical 

 laboratories (List No. 6i). This catalogue, in which 

 everv requisite for the study of plant physiology is 

 listed, with numerous illustrations of special apparatus 

 for phj'siological experiments as well as of general 

 laboratory materials, is indispensable to teachers of 

 botany. The chief feature of the catalogue is the list- 

 ing of the apparatus described in standard text-books 

 on plant physiology ; the portion dealing with botanical 

 material and slides contains a rather large number of 

 misprints in the names of plants. 



Mr. O. F. Cook has published an interesting note 

 in the Journal of the Washington Academy of Sciences 

 (vol ii., No. 9) on the morphology of the leaf in 

 various members of the Prunus section of Rosaceae, 

 sometimes regarded as a separate family (Amygdala- 

 ceae). The leaves of plum, peach, apricot, &c., have 

 a joint at the base, just above the insertion of the 

 stipules, as in many leguminous plants ; the part below 

 this joint does not fall off with the leaf-stalk, but 

 remains alive and forms a supplementary bud-scale. 

 This is regarded as a vegetative character which 

 supports the view that the Amygdalaceje are deserv- 

 ing of family rank, and also as strengthening the 

 connection between the rosaceous and leguminous 

 series. The fact that small leafy outgrowths some- 

 times replace the nectaries on the upper part of the 

 leaf-stalk in various .'\mygdalaceae suggests the view 

 that the immediate ancestors of this family had com- 

 NO. 2242, VOL. 90] 



pound leaves, these nectaries corresponding to the 

 marginal glands of the leaf-blade and representing 

 rudiments of divisions of compound leaves. 



Mr. F. W. Clarke returns to the consideration of 

 the average composition of various rocks in a paper 

 on some geochemical . statistics (Proc. Amer. Philo- 

 sophical Soc, vol li., 1912, p. 214). His results give 

 us an average igneous rock with a silica percentage 

 of about 60, and the " surprising conclusion " (p. 227) 

 that the volume of limestones in the crust is less than 

 that of the salts dissolved in the ocean. The relation 

 of these salts to the earth's age is again referred to. 



Dr. Vaughan Cornish considers the origin of the 

 Jamaica earthquake of January 14, 1907, in a short 

 paper in The Geographical Journal for September. 

 In his account of the earthquake published in the 

 same journal for March, 1908, he shows that the 

 destructive intensity of the earthquake was almost 

 limited to a narrow zone crossing the island from 

 near Kingston to Buff Bay on the north coast. The 

 earthquake evidently originated in two foci, one near 

 the mouth of the river Hope, a few miles east of 

 Kingston, the other about ten miles to the north in 

 the neighbourhood of the head-waters of the river at 

 Hardware Gap. The earthquake could be assigned 

 to no known fault, but, as shown by the small extent 

 of the area of destruction, the depth of the foci must 

 have been inconsiderable. Dr. Cornish therefore 

 attributes the earthquake to the redistribution of 

 stresses in the surface-crust through the action of 

 river-denudation, the added load near the mouth of 

 the Hope river causing a subsidence along a shallow- 

 seated fracture, while the diminution of pressure 

 among the mountains at Hardware Gap would, he 

 thinks, result in elevation along another fracture. 



The report of the Sonnblick Society directs attention 

 to the fact that in September, 191 1, the Sonnblick 

 Meteorological Observatory, at an altitude of 3105 

 metres, completed the tweniy-fifth year of its useful 

 work. It is the highest in Europe which has a resident 

 staff all the year round, and was established by the 

 Austrian Meteorological Society at the instigation of 

 Hofrath Dr. J. Hann. At the end of 1892 it was in 

 danger of being relinquished owing to the want of 

 funds, when the Sonnblick Society was formed and came 

 to its rescue by obtaining subscriptions, which are 

 still continued. Later on the permanency of the estab- 

 lishment was assured by a Government grant in aid. 

 The following data are extracted from the published 

 results for 19 11 : — 



January July Ye:ir 



Mean temperature (C.) - I3'4' ... 2'2° ... - 5-9° 

 Absolute maximum ... - 4^4 ... io"r ... ici 



,, minimum ... - 28 5 ... - 5'6 ... -28'5 

 The melted snow and rain for the year amounted to 

 1398 mm., on 229 days. Rain was only measured on 

 a few days from June to September. Fog occurred on 

 230 days. 



In the Journal of the Meteorological Society of 

 Japan (vol. xxxi.. No. 7) Mr. G. Ishida describes some 

 experiments carried out at Hamada with the view of 

 improving the efficiency of storm warning signals at 

 night. In the tests two kinds of oil lamps were 

 used, provided respectively with circular and fiat wicks. 



