February 6, 1896] 



NATURE 



327 



spread of the contagion, and the successful manner in which 

 outbreaks were restricted is ascribed to such disinfection having 

 been carried out on the same lines as those laid down in the case 

 of tuberculous infectious material. On the whole the report does 

 not throw any important fresh light on this mysterious disease, and 

 its latest appearance in epidemic form does not appear to have 

 differed very materially from that which has characterised 

 previous outbreaks. No reference is made to the bacteriology 

 of influenza. 



An important and most elaborately conducted inquiry has 

 recently been made by Dr. Losener on the opportunity for 

 spreading disease offered by the burial instead of cremation of 

 infected carcases. The actual conditions attending the process 

 of burial were as far as possible faithfully followed, both as 

 regards the depth of the hole and the enclosure of the carcase. 

 The duration of vitality of the various pathogenic microbes under 

 such circumstances was found to vary very considerably. Thus 

 typhoid bacilli only on one occasion survived the processes of 

 putrefaction 96 days, cholera vibrios could not be detected after 

 28 days, tubercle bacilli lived from 95 to 123 days. Tetanus 

 bacilli were, however, still in a highly virulent condition even 

 after 234 days, but after the lapse of 361 days they were no 

 longer discoverable. The bacillus pyocyaneus lived up to 33 

 days, and Friedlander's pneumonia bacillus 28 days ; whilst 

 anthrax germs retained their full complement of virulence during 

 the whole year over which the investigations extended. As 

 regards infection of the surroundings, the information is so far 

 satisfactory, inasmuch as only in the case of anthrax germs were 

 they discovered to have found their way to the adjacent soil and 

 water. So admirable a barrier, however, is provided by the 

 soil, that the earth close beneath the bottom of the hole 

 containing the infected carcase, was in every case found 

 to be quite devoid of pathogenic germs. The bacterial 

 purification effected by filtration through soil has been 

 shown by the Massachusetts experiments on sewage in 

 which five feet of garden soil and five feet of peat were 

 respectively used. So few microbes found their way 

 through, that they were not attributable to the filtration itself, 

 but rather to post-filtration sources. Of course for practical 

 filtration purposes these materials are not available, as they work 

 so very slowly, but the results obtained with them help to 

 support Dr. Losener in his reassuring views as to the hygienic 

 aspects of burial. 



A PAPER of considerable interest, contributed by Dr. F. 

 Ahlborn to the current number of one of our best-known 

 contemporaries, contains a novel application of rowing to biology 

 {Zeit. f. wiss. Zoo/., Ixi., December 1895). The main object 

 of the paper is to explain the use and meaning of the asym- 

 metrical types of tail-fin which are so commonly met with 

 among fishes — e.g. the upturned tail of the shark and sturgeon, 

 and the downwardly extended fin of the flying-fish. Dr. 

 Ahlborn's explanation is founded on a recent suggestion of Prof. 

 F. E. Schulze's in regard to the tail of Ichthyosaurus, and is 

 illustrated by comparisons presumably drawn from the author's 

 own experiences in the art of rowing. Every tyro knows the con- 

 sequences which ensue if he holds his blade too obliquely in the 

 water. If the upper edge is inclined too much towards the 

 stern of the boat, a brisk pull upon the handle results in the 

 blade jumping out of the water, and the oarsman falling back- 

 wards from his seat ; if, on the other hand, the blade is inclined 

 too much in the opposite direction, it digs into the water and 

 the oarsman "catches a crab." The relevance of these illus- 

 trations is found in the fact that the skeletal support of the 

 asymmetrical tails of fishes is generally such that either the 

 upper or lower border of the fin is more resistant to the pressure 

 :>f the water than the opposite border, a fact which causes the 

 NO. 137 1, VOL, 53] 



fin in action to assume an oblique, instead of a vertical position. 

 The result of such a disposition is that in those cases where the 

 upper part of the tail is stiffer than the lower the tail in 

 locomotion is driven upwards, as the oar is driven out of the 

 water (heterocercal tail of shark and sturgeon); while in cases 

 where the lower part of the tail is firmer than the upper the 

 tail tends, in action, to assume a lower position than the rest of 

 the body (flying-fish). The body of the animal, in fact, is made 

 to swing vertically about a horizontal axis running through the 

 centre of gravity : in the first group the tail becomes elevated 

 above the head, in the second group the head becomes raised 

 above the tail. The utility of these types of organisation 

 becomes obvious when we reflect, with Dr. Ahlborn, upon the 

 habits of the creatures which exhibit them. The first group 

 consists of bottom-haunting fish, which are thus enabled to give 

 free play to their tails while scouring the sea-bottom in search 

 of food ; the second consists entirely of surface-swimming forms 

 which are enabled, by this beautiful adaptation of structure, to 

 swim swiftly beneath the surface of the water without the risk 

 of their tails emerging, and so causing inconvenience and waste 

 of force. The tails of many air-breathing aquatic animals, such 

 as the crocodile, water-snake, and the extinct Ichthyosaurus, 

 are constructed upon this latter principle. 



The number of the Trinidad Field-Naturalists' Club for 

 October 1895, contains an elaborate paper by Mr. T. I. Potter, 

 on four species of Oncidium, natives of the island. 



The Field Columbian Museum has commenced the issue of a 

 series of botanical papers, with a contribution to the Flora of 

 Yucatan, by Mr. C. F. Millspaugh, botanical curator, illus- 

 trated by several photographs. The orders which are most 

 numerously represented in the Peninsula are the Legum inosai 

 and the Composite:. 



Attractive, but somewhat belated, are the Brochures 3 and 

 4 of vol ii. of the Proceedings of the Rochester Academy of 

 Science, just received by us. The papers contained in these 

 publications were, for the most part, read before the Society in 

 1893. Among the subjects treated are : "The Evolution of the 

 Ungulate Mammals," by Prof. H. L. Fairchild ; "Solar Elec- 

 trical Energy not transmitted by Radiation" by Dr. M. .\. 

 Veeder ; and " The Pitch Lake of Trinidad," by Mr. A. 

 Cronise. 



Thk tdiiox oi Just's Botaniscker Jahresbericht has issued an 

 appeal to all botanists for a prompt despatch of separate copies 

 of their contributions to scientific journals, or other botanical 

 treatises. The average number of such papers, an abstract of 

 which is given in each year's Bericht, is about 5300 ; and of 

 these the editor has never received, up to the present time, 

 copies of more than 300. The papers should be addressed to 

 the Editor, Prof. Dr. E. Koehne, Kirchstrasse 5, Friedenau- 

 Berlin. 



Vol.. iii. No. 6 of the Contributions from the U.S. National 

 Herbarium consists of an interesting account of the botany of 

 Yakutat Bay, Alaska, by F. V. Coville, to which is prefixed a 

 general report on the characteristics of the Flora, by F. Funston. 

 Even in August the danger in crossing the bay in canoes is very 

 great from the floating ice. The country is largely covered by 

 impenetrable forests of the Sitka spruce, Picea sitcAensis. The 

 number of species of vascular plants gathered was 137, the pre- 

 dominant orders being Ranunculacex', Rosacete, Compositi«, 

 and GramincK. 



Bulletin No. 9 of the " Minnesota Botanical Studies " for 

 189s contains an interesting article, by Mr. R. W. Squires, on 

 Tree-temperatures. The observations were made between 



