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particular. “In 1883 innumerable were the cases in which I observed that the descending stripe on the leaves was dried out and stopped, so that the bulb was not attacked.” The rapidity of the infection depends largely on the temperature, the dampness in the surrounding air, and on the amount of water in the plant itself. The location of the wound might also make a difference.

(4) Methods of Prevention. -An inquiry among the growers elicited the statement that there is a great difference in sus. ceptibility. This Dr. W. thinks cannot be denied. Some varieties are very subject; others, in the same beds or gardens, have not been known to be attacked. Many varieties formerly held to be exempt from the disease are now known to be subject; but some remain which have never yet shown the yellow disease, and this cannot be ascribed to mere accident; on the contrary, it can be explained only by assuming that predisposition or readiness to be attacked here plays a prominent part (Verslag, 1883). Anatomically, so far as known, all are alike. Lists of "very susceptible,” “ less susceptible” and “not susceptible” varieties are given, from which it would appear that single varieties are more susceptible than double ones, and the exemption of the latter is not due to their lesser number. All of the double red varieties and most of the other double sorts are exempt, or but little subject to attack. These lists are based on statements furnished by only seven growers, but include many varieties (Verslag, 1885). Of thirteen varieties said to be very susceptible by several or most of these seven growers only one is double, la Tour d'Auvergne. On this account, difference in receptivity is suggested as a means of combatting the disease. New varieties must not be originated from susceptible ones. Seedlings should be derived from hardy sorts, and by artificial fecundation, the pollen of susceptible varieties being excluded. Otherwise, through the agency of insects, the resulting cross may prove susceptible. The law of heredity is shown still more rigorously in non-sexual reproduction. It is best, therefore, to discard sensitive sorts and try to obtain new ones which are more robust.

In the division of bulbs for propagation the greatest care should be taken never to cut a healthy bulb with a knife which has been in contact with a diseased plant, at least not until it has been disinfected.

There is another point to which the author desires to call special attention, viz., to the removal of leaves which begin to show signs of the disease at the tip. On May 20, 1883, the diseased leaves were entirely cut away from seventeen hyacinth plants. On September 26th, sixteen of these bulbs were entirely sound, although rather small. The other bulb was entirely decayed; but from what cause, it was no longer possible to determine. Planted in pots these sixteen bulbs blossomed in April, 1884. The following June they were dug up once more, and on cutting them open all were found to be sound. This experiment was tried on many other bulbs, and always with the same success. It was also tried by several horticulturists in their fields with results entirely confirmatory. It is, therefore, certain that the bulb can be preserved by the judicious removal of diseased leaves.

Since the bacteria have always penetrated much further into the leaf than is to be seen with the naked eye, the whole leaf should be removed even when only slightly attacked. The frequent complaint that cutting off the diseased parts does no good, shows that not enough attention has been paid to this. Of course, when the bulb is already infected, cutting off the leaves amounts to nothing (31).

Finally, it goes without saying that the debris of diseased hyacinths should not be left in the field or near it, as one might be tempted to do on account of its value for manurial purposes. All such debris should be thrown into a deep ditch and disinfected with quick lime.

Remark.—Considering the time when this piece of work was done, it is remarkably good, and in all of the papers cited the internal evidence indicates a careful, conscientious, brilliant investigator. There can be no doubt that the disease is due to a bacterial parasite; but to complete the proof that the disease is due to the specified organism it should be obtained by infections with pure cultures obtained from single colonies. The organism thus isolated should also be studied under a wider range of artificial conditions than were employed. Indeed, excluding the pathogenic test, it is more than doubtful if the organism could be identified from the description.

EDITOR'S TABLE.

The rules of zoological nomenclature formulated by Strickland and adopted by the British Association for the Advancement of Science, in 1842 have been observed by most zoologists ever since. They are eminently fair, and conducive to the best interests of science, and in broad contrast in certain details to some individual opinions which have been promulgated in recent years.

There is a minor point in which it seems to us that the Stricklandian rule might be amended, and we recommend it to the consideration of the international zoological congress committee on nomenclature. This is the question of the presence or absence of the annectant i in the root of proper names of the second declension—to which most proper names belong. Shall we write Boggsus or Boggsius : Keenus or Keenius; Levius or Leviius, etc.? The British rule provides (Proceeds. Brit. Ass. Adv. Sci., 1842, p. 115) that after a consonant the termination of proper names shall be us gen. i ; while after a vowel the i shall be inserted, so that we have ius, gen. ii.

This rule, however, does not exactly conform to the usage of the Romans, which was not regular. Thus they wrote Catullus, Catulli, but Sallustius, Sallustii ; Corvus, Corvi; Horatius, Horatii, etc. After vowels the custom also varied, but generally the i was omitted since it is unnecessary on the score of euphony. The Romans were, as well known, guided by euphony in the matter, hence the irregularity. It is evident that we should be guided by the same principle, but that in doing so we should endeavor to formulate a rule which shall have no exceptions. Naturalists cannot be expected to remember exceptions in a subsidiary matter like nomenclature.

The reversal of the Stricklandian rule would apparently accord best with the spirit of Latin word composition. That is, an i should be inserted after the root of all proper names of the second declension which ends in a consonant, and no i should be inserted where the root terminates in a vowel. Names of the first class never sound badly with the i, while most of them,-notably those whose roots end in labials and dentals, do sound badly. A vowel precedes the us euphoniously. Thus Dana, Danaus; Perrine, Perrinius; Secchi, Secchius; Gaudry, Gaud. rius. Those ending in o and u are not of the second declension, unless made so by the addition of the consonant v, as Sello, Sellovius; Yarrow,

Yarrovius.

OUR much esteemed contemporary, Natural Science, had, in a recent number, three short articles devoted to the denunciation of the describing of species in biology; calling the practice in one of them “a most unprofitable" kind of work. Now comes our equally esteemed colleague, The Revue Scientifique (1896, p. 440), and remarks as follows, anent of the recent work of Messrs. C. H. Merriam and E.S. Miller on North American Mammalia : “But really is there not more interesting work to be done on the fauna of the United States ? This work, which consists in enumerating and describing species, which is within reach of the most mediocre intelligence, this fastidious care which should be left to those who are not capable of ideas, is this the only work which tempts American Zoologists? Is there not other occupation for their scientific activity? Cannot Mr. Hart Merriam stimulate work of a biologic character?"

We regard the expressions above quoted as an indication of a mild form of megalomania which is not unfrequently found among the users of mechanical appliances in the biological laboratory. The most intelligent cultivators of these important branches of biologic research are, however, well aware that the exact determination of species is fully equal in importance to their own pursuit, for the following reasons, among others. If we regard biology to consist of two branches, evolution and physiology, we define evolution, with Darwin, as the origin of species. For physiology the question of species is not so important. Species are, however, what the labors of the ages have produced, and it is necessary to know them in order to pursue any branch of evolution (as embryology or paleontology) intelligently. The work of the embryologist and paleontologist who does not know the species whose origin he seeks to explain is greatly lacking in precision. Linnæus states that the tyro knows the higher divisions, but only the expert knows species. We also especially deny that the discrimination and description of species is within reach of the most mediocre intelligence. On the contrary, no kind of work in biology imposes as much on all the mental faculties which are used in scientific work. Those who have not attempted it have little idea what is involved in a diagnosis or an analytical key. Finally, as regards the mammalogic work of Messrs. Merriam and Miller, we consider it of the utmost importance. They are pointing out the results of the evolution of Mammalian life in North America, which it is the business of the embryologist and the paleontologist to explain. And in this field the work of Messrs. Merriam and Miller is the best that has ever been done in any country.

The most important result of the Nansen Arctic exploration which has been so far given to the public is the discovery that the ocean has the great depth of nearly 2000 fathoms north of Franz Joseph's Land. This is the average of the oceanic depths, and the knowledge of its extension to the point nearest the pole yet attained, is a distinct gain. It dispels the idea that the pole can be reached overland from the side of Siberia, and shows that the nearest land approach, as suggested by Peary, is by way of Greenland. While this discovery does not destroy the hypothesis that land exists near the pole, it weakens it. The theory will not become extinct until the northern rendezvous of high arctic migratory birds has been discovered. The remarkable discovery of a territory free from glaciers and covered with vegetation in Grinnell Land, and along the north coast of Greenland, by the Greeley Expedition, opens up interesting possibilities, and must stimulate further search. American citizens have had an honorable share in these in the past, and it is to be hoped that they will continue to attack the problem until it is solved.

RECENT LITERATURE.

The Earth and Its Story by A. Heilprin' fills a want long felt by teachers of elementary geology. It is a well illustrated little volume which presents “briefly, forcibly and possibly in a more popular form than in most books of a similar nature, the general facts of geology." It covers the field that it is intended to cover in a remarkably satisfactory manner. The facts of the science are given in sufficient detail to impress the student with the notion that the generalizations based upon them are built upon a secure foundation. Comparatively slight stress is laid upon these facts, the greater emphasis being placed on the general truths to which they lead. The book is interesting. It is well written ; the language is simple and the thoughts are very clearly expressed. Only the most important conclusions of geology are mentioned, and where the views expressed are not accepted by all geologists, the author does not hesitate to mention the fact.

A prominent feature of the book are the illustrations. These are mainly reproductions of photographs, many of them entirely new.

* Angelo Heilprin: The Earth and Its Story, a First Book of Geology. Boston, Silver, Burdett and Co., 1896. Pp. 267 and Plates 64.

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