1 64 



NATURE 



[Dec. 17, I ; 



centric cylinders, made of some hard wood (Fig. i), the outermost 

 2 inches high, the others increasing in height by regular incre- 

 ments of 2 inches up to 18 inches. The cylinders are J- inch 

 thick, except the innermost, which is a solid rod i inch in 

 diameter : they are made so as to slide easily upon one another 

 in any direction. The exposed portion of each cylinder, 2 

 inches in length, represents an internode, its upper edge a node. 

 On the upper edge of each is fixed a small wooden knob (Fig. i, 

 o-S) representing a leaf-insertion, and of such a size as to |iro- 

 ject slightly beyond the"cylinder to which it is attached. By 

 revolving the cylinders these knobs can be made to take up 

 positions representing any divergence from ^ to | ; higher 

 divergences would of course require a greater number of cylin- 

 ders and consequently a larger and more unwieldy apparatus. 

 In the figures the cylinders are shown adjusted to a divergence 

 of 4. The adjustment is facilitated by holding above the model 

 a straight wire in the case of ^ divergence, or a 3-, 5-, or 8- 

 rayed wire star (Fig. 5, A, B, c) in the case of higher diver- 

 gence. The genetic spiral is best shown by winding a piece of 

 string round the model. 



To explain the construction of the leaf-diagram, the whole 

 apparatus is "telescoped" by simply lifting the lower cylinder : 

 as the latter is raised each cylinder in turn is caught by the 

 projecting portion of the leaf-knob of the next higher cylinder, 

 until finally the upper edges — /.(•. the nodes — of all nine are 

 brought to one level, or in other words, the internodes are sup- 

 pressed (Fig. 2). Then by observing the model end-on (Fig. 3), 

 nine concentric circles are seen, each representing a node, and 

 having a leaf-insertion in the appropriate position. To make 

 this clearer, the upper edges of the cylinders are painted alter- 

 nately light and dark, as in Fig. 3. The resemblance of the 

 model in this position to the leaf-diagram is made still clearer 

 by placing over it a straight wire or wire star (Fig. 5) to re- 

 present the orthostichies, and bring out the precise meaning of 

 the angle of divergence. 



For the illustration of whorled arrangements movable leaf- 

 knobs are provided which can be inserted in small holes (Fig. 4, 

 b, <■, d) in the edges of the cylinders. By placing one of these 

 movable knobs in b oppo.site to the fixed knob a, a 2-leafed 

 whorl is produced ; by placing knobs in c and d, a 3-leafed whorl . 

 By revolving the cylinders successive whorls can be made either 

 alternate or superposed. 



I tried at first, some four years ago, a model having all the 

 cylinders of the same height, each fitting rather tightly into the 

 next lower one, which overlapped it about half an inch. But I 

 found it impossible to get this arrangement to work satisfactorily, 

 owing to the irregular contraction and expansion of the wood 

 and the weight of the upper cylinders. 



In addition to this model I find it very useful to have each 

 divergence separately illustrated by a model having the form of 

 a truncated cone iS inches in height. The cone is painted 

 white : black circles are drawn round it at regular intervals to 

 represent nodes, on which black knobs are fixed for leaves : the 

 orthostichies are painted yellow, and the genetic spiral red. In 

 the case of the higher divergences these models are useful for 

 showing the relations of the parastichies and the method of 

 determining the divergence from them. Two secondary spirals 

 running in opposite directions are made by passing two pieces 

 of diiferently coloured string round the cone in opposite direc- 

 tions, each having a turn given to it round each leaf-knob in 

 the parastichy it represents. T. Jeffery Parkek 



Dunedin, N. Z. , October g 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Cambridge. — Dr. Vines has been appointed Honorary 

 Secretary of the General Board of Studies for business con- 

 nected with the lists of lectures issued by the Board. 



Dr. A. S. Lea, Fellow of Gonville and Caius College, has 

 been approved for and admitted to the degree of Doctor in 

 .Science. 



A temporary iron dissecting-room for Human Anatomy is to 

 be erected on space adjacent to the present Anatomical Schools. 

 Over 145 men are engaged in dissection this term. 



The honorary degree of Master of Arts has been conferred on 

 Mr. Walter Heape, Demonstrator of Animal Morphology. 



The Public Orator (Mr. J. E. Sandys), in presenting Mr. 

 Heape for the degree, observed that Mr. Heape, quantum intiv 

 lucrum el laudcm intersit expertus, had relinquished the brilliant 



prospects open to him in a mercantile career and had deliberately 

 preferred to devote himself to scientific pursuits. In 1879 he 

 was attracted to Cambridge by the high reputation of the late 

 Mr. F. M. Balfour, and after working with him for three years 

 in the newly-founded Morphological Laboratory, he had, during 

 the three years that had elapsed since Prof. Balfour's lamented 

 death, done good service as Demonstrator of Animal Morpho- 

 logy. In prosecuting his favourite studies he had considered 

 nothing too small, nothing too great, for his attention ; he had 

 not only investigated the early development of the mole, but 

 had also secured for the University Museum an exceedingly rare 

 specimen of a wild male .-Vfrican elephant, which he had killed 

 with his own hand in the South of Africa. " Magnum profecto 

 est ultima ex Africa spoliis opimis onustum redisse ; laudem vero 

 majorem eidem distinat virtus — 



" Diadema tututn 

 Deferens uni, propriamque laurum, 

 Quisquis ingentes ( 



Spe, 



An examination for two minor Scholarships will be held at 

 Downing College on June I, 2, and 3, 1886. The examination 

 in Natural Sciences will include most of the subjects of the 

 Natural Sciences Tripos except Geology and Mineralogy, but 

 no one will be examined in more than three subjects, and great 

 weight will be attached to proficiency in one subject. 



The Clothworkers' Exhibition of 52/. io.t. a year for Physical 

 Science has been awarded to Mr. G. A. Shaw ; the Exhibition 

 of 30/. to Mr. J. Morgan. 



The Antiquarian Museum is growing in value by the dona- 

 tions, both general and local, which it has received. The 

 Curator, Baron von Hiigel, has accomplished much in the 

 arrangement of the objects, and has himself deposited valuable 

 collections on loan. 



SCIENTIFIC SERIALS 



The Botanical Gazette (Indianapolis) for September and Oc- 

 tober is chiefly occupied by a report of the papers read in the 

 Botanical Section of the American Association for the Advance- 

 ment of Science at its Ann Arbor meeting. These furnish 

 satisfactory evidence of the good work doing in this branch of 

 science on the American continent, and will not suffer from 

 comparison with a similar record at any of the recent meetings 

 of our own Association. The following are the titles of the 

 papers read : — ^J. C. Arthur, proof that Bacteria are the direct 

 cause of the disease in trees known as pear-blight. — C. R. 

 Barnes, the process of fertilisation in Campanula americana. — 

 C. E. Bessey, the question of bi-sexuality in the Zygnemace^e. 

 — C. E. Bessey, further observations on the adventitious inflor- 

 escence of Ctiscuta glomerata. — T. J. Bunill, the mechanical 

 injury to trees by cold. — D. H. Campbell, the development of 

 the prothallia of ferns. — J. M. Coulter, on the appearance of 

 the relation of ovaiy and perianth in the development of dico- 

 tyledons. — W. G. Farlow, notes on some injurious fungi of 

 California. — E. L. Sturtevant, an observation on the hybridisa- 

 tion and cross-fertilisation of plants. — E. L. Sturtevant, ger- 

 mination studies. — As far as these papers are reported here, we 

 may note Mr. Arthur's, Mr. Barnes's, Mr. Campbell's, and Mr. 

 Coulter's as giving especially good evidence of a capacity for 

 original work. Another interesting feature of this number is 

 the report of the proceedings of the "Botanical Club," which 

 held daily meetings during the session of the Association, with 

 an attendance in all of no less than eighty-five members. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, November 19. — "On Variations in the 

 Amount and Distribution of Fat in the Liver-Cells of the Frog." 

 By J- N. Langley, M..\., F.R.S., Lecturer on Histology in the 

 University of Cambridge. 



The fat in the liver-cells is at its maximum amount in Feb- 

 ruary and March. In April it rapidly decresses ; from May 

 until December it is present in comparatively small though 

 varying amount. 



Generally speaking, the fat globules form an inner zone in 

 frogs which have hungered more than a week. In January, 

 February, and March, however, the fat-globules are commonly 

 more numerous in the outer part of the cells, often forming a 

 distinct outer zone. 



