December 4, 1919] 



NATURE 



359 



us what we want. I hope meetings of this sort will 

 be continued in years to come, and that we shall be 

 able to interest the Institution of Electrical Engineers 

 in our work as electro-therapeutists and radiologists. 

 It is a fascinating subject, and a far-reaching one for 

 humanity — that is, the future of the electrical and 

 radiological treatment of disease Perhaps my 

 optimism is enormous." It is this spirit of optimism 

 that has buoyed up Dr. Lyster through his times of 

 suffering, and caused him to remain at his post to 

 the last. 



Dr. J. Walter Fewkes, Chief of the Bureau of 

 .\merican Ethnology, has recently returned from two 

 months' field-work on the Mesa Verde National Park, 

 Colorado. This park is the only one reserved by the 

 U.S. Government for the protection of aboriginal 

 buildings, and for the last decade the Department 

 of the Interior and the Smithsonian Institution have 

 co-operated in the excavation and repair of ruins in 

 order that they may be preserved for posterity, after 

 having been put in a condition to show their 

 structural features. The field-work of last summer 

 was devoted to a cliff-dwelling called Square Tower 

 Mouse from a high tower situated midway in its 

 length. This tower is 40 ft. high, and is the highest 

 building constructed of masonry by Indians north of 

 Mexico before the coming of the whites. It adds to 

 this unique feature the best-known example of pre- 

 historic masonry, shown in the construction of the 

 roofs of two circular rooms. The original rafters 

 ,-ire still in place, showing the marks of stone im- 

 plements used bv the builders. The whole ruin, which 

 measures 136 ft. in length, is most picturesquely 

 situated, anil has already become one of the greatest 

 attractions of the park. An unexpected result of the 

 field-work was the discovery of many inconspicuous 

 buildings among the cedars on top of the plateau. 

 The evidences of these buildings before excavating 

 were verv obscure, but they are so numerous in certain 

 areas that there is scarcely a square quarter-mile in 

 which one of them does not occur. One of these 

 small buildings when excavated was found to belong 

 to a very ancient type, probably the oldest on the mesa. 



We have received the second number of Medical 

 Science, a monthlv periodical of abstracts and reviews 

 of medical science published bv the Medical Research 

 Committee. The present issue contains, among 

 others, reviews on diphtheria, tuberculosis, gastric 

 ulceration, influenza, and cerebro-spinal fever. In 

 the last-named, Dr. RoUeston surveys the epidemio- 

 logy, symptoms, and treatment of the disease, par- 

 ticularly with serum. This, in the hands of numerous 

 observers, has proved to be of benefit, reducing the 

 mortality provided it is administered early enough. 



.\ SHORT, but very welcome, account of the court- 

 ship of the dabchitk, by Mr. Julian Huxley, appears 

 in British Birds for November. The author was too 

 late to witness the earlier phases of the courtship, but 

 he contrived to glean much information as to their 

 behaviour after pairin^-up had taken place. These 

 birds, lacking the frills and crests characteristic of 

 other species of grebes, display none of the posturing 

 which takes place in the more' resplendent species, but 

 content themselves with the performance of duets re- 

 calling the neighing of a horse. They also spend 

 much time in long excursions on the water, swirnming 

 side bv side. It is to be hoped that next year it will 

 be possible to start observations earlier in order that 

 the initial stages of the courtship may be studied. Mr. 

 Huxlev's studies on the courtship of the great crested 

 grebe are known to all ornithologists, and his able 

 handling of this theme makes us the more anxious to 

 have the complementary picture. 

 NO. 2614, VOL. 104] 



In an important memoir on a new type of nephridium 

 found in Indian earthworms of the genus Pheretima 

 {Quarterly Journal of Microscopical Science, vol. Ixiv., 

 part i) Mr. Karm Narayan Bahl gives a very interest- 

 ing description of the excretory system of Pheretima 

 posthuma. He finds three distinct kinds of nephridia 

 in this worm : septal, pharyngeal, and integumentary. 

 Although the nephridia are very numerous and all 

 small (micronephridia), the system "is not plectonephric, 

 each nephridium being a separate organ. The chief 

 novelty of the author's work lies in the discovery that 

 the septal nephridia open into the intestine, instead of 

 on to the surface of tlie body, by segmentally arranged 

 apertures, not directly, but through a system of ducts, 

 of which the most important are a pair of longitudinal 

 excretory canals lying above the intestine, one on 

 each side of the mid-dorsal line. The author applies 

 the term " enteronephric " to this remarkable type of 

 nephridial system, and puts forward the suggestion 

 — due to Prof. W. N. F. Woodland— that the dis- 

 charge of the excretory products into the intestine may 

 be a special adaptation for the conservation of mois- 

 ture in a dry climate. 



The Journal of the Board of Agriculture for 

 October contains a preliminary report on the recent 

 Lincoln tractor trials. The excellent work done by 

 the machines and the large attendance of farmers 

 show that the industry has now passed the jiioneer 

 stage. The tendency of the manufacturers is less to 

 novelty of design than to development in accordance 

 with the experience obtained in this country, chiefly 

 as the result of the operation of the Government 

 tractor scheme. Close attention is being paid to the 

 reduction of weight, to the increased accessibility of 

 the vital parts of the machinery, and to the provision 

 of protection from the effect of weather and dirt. 

 Interesting comparisons were made of the ploughing 

 done bv tractors fitted respectively with high-speed 

 vertical and low-speed horizontal engines, with wheels 

 and caterpillar-tracks, and between self-contained 

 machines and independent tractors. The use of the 

 tractor is not restricted to ploughing, and there were 

 important haulage tests and threshing demonstrations. 

 Great as is the value of the present trials from 

 the commercial and educational points of view, 

 further trials extending over a considerable interval, 

 and giving greater uniformity of task and conditions, 

 will be necessary before the capacity of the various 

 machines can be defined. 



The Ke-w Bulletin (Nos. 6 and 7, igiq) contains an 

 account of recent investigations by J. Bintner on the 

 symptoms and distribution of silver-leaf disease. 

 There has been much controversy as to the cause of 

 the disease, which is now established as mainly due 

 to the growth in the tissues of the mycelium of the 

 fungus Stereum purpureum. Mr Bintner demon- 

 strates the presence of the fungus in the wood _ of 

 diseased branches, which show the brown coloration 

 beneath the bark characteristic of the disease. No 

 trace of the fungus has been found in the leaves, and 

 it is suggested that the separation of the cells, which 

 gives the silver effect, is caused by the production of 

 some diffusible toxin by the fungus, which is con- 

 veyed to the leaves in the water-conducting channels. 

 Infection takes olace through open wounds above 

 ground and immediately below ground-level, and 

 inoculation experiments confirm the view that injured 

 superficial roots can be infected. Localised silvering 

 of a branch results from local infection which has not 

 yet spread to the main stem, and excision of the 

 diseased branch mav save the tree. On the other 

 hand, silvered suckers springing from a healthy tree 

 indicate root-infection, and where root or stem is 



