December 21, 191 1] 



NATURE 



249 



not prove that the city proper covered such a great 

 area as Mr. Maler states. 



To those who have not studied American 

 archaeology, it is a surprise to learn that the remains 

 of a city covering nearly a square mile, with five great 

 stone-built temples, raised on pyramidal foundations, 

 the highest reaching an elevation of nearly two 

 hundred feet from the ground, as well as many smaller 

 temples of similar form, and well-built stone houses 

 containing numerous small, stone-roofed chambers, 

 are to be found hidden away in the depths of a 

 tropical forest in America. However, American 

 archaeology is still in its infancy, and may have some 

 -strange developments in store for us; it is a vast field, 

 and as the interest in it is rapidly increasing, there 

 IS every hope that the rising enthusiasm of students 

 and explorers will result in dispelling much of the 

 mist which obscures the curious civilisations, some 

 of which developed and waned many hundreds of 

 vears before the first Spaniard set foot on the 

 American continent. Mr. Maler probably closes a 

 long career of exploration in the forests of Guatemala 

 md Yucatan with his last journey to Tikal, but from 

 Dr. Tozzer one can happily look for useful and con- 

 scientious work, both in the field and in the study for 

 many years to come. Alfred P. Maudslay. 



THE ECOLOGY OF DESERT PLANTS. 

 T N a publication of the Carnegie Institution of Wash- 

 *■ ington, entitled "The Water-Balance of Succulent 

 Plants," Mrs. E. S. Spalding adds to the statistics 

 that she had previously given concerning the reversible 



changes in dimensions 

 and form of Cereus 

 giganteiis, the massive 

 stem of which acts as 

 an expanding and con- 

 tracting water-reservoir. 

 Her observations on the 

 rate of growth of this 

 " giant cactus " lead to 

 ,the conclusion that it 

 requires a hundred 

 years to attain a height 

 of ten metres. Mrs. 

 Spalding shows that 

 analogous reversible 



change in volume takes 

 place in Echinocactus 

 Wisliz-e-ni, and Opun- 

 tia spp., and gives the 

 interesting information 

 that the former, at 

 first spherical in form, 

 becomes irregularly 

 columnar, lop-sided, 

 and top-heavy, so that 

 it readily topples over 

 or is uprooted by the 

 wind. She suggests 

 that the inefficiency of 

 the root-system thus 

 revealed represents a 

 case of incomplete 

 adaptation, which 

 accounts for the " sparse occurrence " of the plant. 



By the somewhat cryptic and certainly inelegant 

 ':xpression "water-balance," Mrs. Spalding and her 

 co-author, Prof. D. T. Macdougal, mean the amount 

 of water stored in the plant. The latter author's con- 

 tribution to the work includes statistics as to the rate 

 and amount of loss of water of certain succulent 

 NO. 2199, VOL. 88] 



Kir,, z.— Cereus giganteus having a 

 dead trunk and living liranclu-^ 

 which bore flowers one year after 

 the death of the trunk. 



plants, including the three species mentioned above ; 

 for instance, he concludes that individuals of Cereus 

 giganteus " 12 to 20 metres in height would contain 

 from 2000 to 3000 litres of water," and that "such 

 individuals might lose from 1000 to 1600 litres of 

 water . . . and still survive." As an excellent 

 example of the power of endurance displayed by this 

 species under net loss of water, Prof. Macdougal 

 mentions that branches may remain alive and even 

 bear flowers many months after the death of the 

 main trunk. A number of successful photographs 

 illustrate the work, and one of these is reproduced 

 here. 



SIR JOSEPH D ALTON HOOKER, O.M., G.C.S.L 



F.R.S. 

 'HTHE most distinguished son of a very distinguished 



■*■ father, Joseph Dalton Hooker was born at Hales- 

 worth, in Suffolk, on June 30, 1817. Early in 1820 

 his father was appointed by the Crown to fill the chair 

 of botany in the University of Glasgow, a post which 

 he held until, in 1841, he became director of the Royal 

 Gardens at Kew. As a consequence Hooker was 

 educated in Glasgow, passing through the High 

 School to the University, from which he obtained the 

 degree of M.D. in 1839. Devoted as a lad to the 

 reading of works of travel, we learn from Hooker 

 himself that he was especially impressed by Turner's 

 description of the Himalayan peak of Chu'mlari, and 

 by the account of the Antarctic island of Kerguelen 

 contained in Cook's voyages. An opportunity of 

 investigating the latter came to him very early in his 

 career. When he completed his medical studies. 

 Hooker entered the Royal Navy as an assistant 

 surgeon, and was gazetted to the Erebus, then about 

 to start, along with the Terror, on the famous Ant- 

 arctic expedition led by the eminent navigator Sir 

 James Clark Ross. Throughout this expedition the 

 young assistant surgeon held the post of botanist, and 

 during its three years' cruise in the southern seas he 

 was able to visit New Zealand, Australia, Tasmania, 

 Kerguelen, Tierra del Fuego, and the Falkland 

 Islands, amassing large collections and acquiring a 

 vast amount of botanical information. 



Shortly after the close of this expedition, Hooker, in 

 1843, became assistant to Graham, then professor of 

 botany in the University of Edinburgh, and in 1845, 

 when Graham was succeeded by the elder Balfour, 

 Hooker was appointed botanist to the Geological 

 Survey of Great Britain. Much of his time during 

 this period was devoted to the preparation for publica- 

 tion of the results obtained during the course of his 

 Antarctic voyages. But in 1847 ^^is work was tem- 

 porarily suspended, and his appointment on the 

 Geological Survey was relinquished, in order that 

 Hooker might add, by further travel, to his first-hand 

 knowledge of the vegetation of sub-.Antarctic and tem- 

 perate regions, a corresponding acquaintance with the 

 botany of tropical countries. The region selected was 

 north-eastern India, then a practically unexplored 

 tract. The undertaking, originally designed as a pri- 

 vate enterprise, through a series of happy accidents 

 received official recognition, and the expenses involved 

 were to a partial extent met from public funds. 

 Hooker left England in November, 1847, reaching 

 India in January, 1848. .-Vfter some three months 

 spent in the Gangetic Plain and Behar, during which 

 he ascended the sacred hill of Parasnath, Hooker 

 made his way to the Himalayas, reaching Darjeeling 

 in Sikkim in the middle of April. The next two years 

 were devoted to the botanical exploration and topo- 

 graphical survey of the Himalayan state of Sikkim 

 and of a number of the passes which lead from that 



