December 14, 191 1] 



NATURE 



2 1 



which are of great interest and value. Many move- 

 ments in nature proceed at a rate such that we cannot 

 successfully follow them with the eye and brain. The 

 slow movements of a leucocyte, the gradual unfolding 

 of a flower-bud or upward growth of a plant advance 

 so leisurely that we cannot readily follow the change 

 — it is only by observing them from time to time that 

 we can appreciate that alteration is occurring. A suc- 

 cession of photographs, however, taken at consider- 

 able intervals, and passed rapidly in review before us, 

 shows us as occurring in a few minutes the whole 

 ])rocess which may take hours or days in reality, and 

 we are better able to appreciate the nature of the 

 phenomena because the sequence becomes more 

 obvious. Conversely, many motions occur too fast for 

 us to analyse them. The fact that our retina can 

 clearly distinguish only impressions which reach it at 

 a comparatively slow rate makes it impossible for our 

 unaided eye to follow the sequence of many natural 

 phenomena. By reproducing at a slower pace the 

 changes which do occur, the kinematograph can assist 

 us to attain a clearer perception of the nature of the 

 alteration which is taking place, or, even if we are 



amoeboid movements of a leucocyte or a spirillum 

 wriggling its way between the corpuscles or the heart 

 itself beating before their eyes. Yet these are things 

 which it concerns them to understand, and no amount 

 of imagination can supply the clearness and com- 

 prehension which actual seeing can give. The kine- 

 matograph might well become a most efficient aid to 

 the teaching of very many biological, and especially 

 medical, subjects. 



The accompanying illustrations have been reproduced 

 from kinematograph films kindly supplied for the pur- 

 pose by Messrs. Pathe Freres. 



THE RUBBER-PRODUCING PLANT OF THE 

 MEXICAN DESERTS.' 



A MONGST the botanical collections formed in 

 ^~^ 1852 by Dr. J. M. Bigelow, whilst attached to 

 the Mexican Boundary Survey, w'ere specimens of a 

 shrub known to the Mexicans as "guayule," after- 

 wards described by Prof. Asa Gray as Parthenium 

 argentatutn. No mention, however, was made of its 



||||^.l--*^^-' 



,H«||»?--1»f«»*¥^' 





Fig. I. — Foot-slope of Sierra Zuluaga 



Still unal^le to grasp the successive phases, a study 

 of the film itself will enable us to follow the sequence 

 and analyse the motion with a greater detail and a 

 greater accuracy than any number of examinations of 

 the natural phenomenon can possibly supply. The 

 kinematograph therefore can give us a positive addition 

 to the sum of our knowledge, as well as diffuse 

 through wider circles knowledge already gained. 



This latter, while perhaps the most obvious, is 

 not the least of the functions which such moving 

 pictures can fulfil. There are thousands of people in 

 this country who are intimately acquainted with the 

 cellular constituents of the blood, and their various 

 shapes and functions, thousands who have seen the 

 ordinary bacterial preparations or are familiar with 

 the heart-beat and its action on the pulse, but of these 

 thousands not one-tenth have actually seen the 



NO. 2198, VOL. 88] 



rubber-bearing qualities. It was not until 1876 that 

 public attention was directed to guayule rubber by 

 an exhibit sent to the Centennial E.xposition at Phila- 

 delphia in that year. The country peon had, it ap- 

 peared, for long been in the habit of making playing 

 balls and other articles by the " communal mastica- 

 tion " of the bark of this shrub, and it was by that 

 means sufficient was obtained for the above-mentioned 

 exhibit. Investigation showed that the plant was 

 capable of producing in the neighbourhood of ten 

 per cent, of its weight of dry rubber, and that it grew 

 in vast abundance in the desert country of northern 

 Mexico. 

 This (Hscovcrv speedily changed the economic value 



' :iuni argcntatum, <; ,\ i Ivii' ' ■ i [ilant of the 



Chiliu„: .,'...... Uy ProfT F. E. Llu>d. I'p- via i ^11 + 46 plates. 



(Washington: Carnegie Institution, 191 1.) Publication No. 139. 



