with the spark has the same effect as increasing the current. It is possible to obtain the glow from hot calcium oxide providing the discharge is kept very small. The shape and position of the electrodes have no appreciable influence on the production of this glow. It is produced equally well from platinum and from iron electrodes and in tubes made from soda and from lead glass. It does not appear to depend on the purity of the mercury. It requires approximately .001 sec. for the glow to die out after the exciting current has ceased. As a result of this continuance of the glow the radiators may continue to give light while being carried with the current of mercury vapor for 20 or 30 cm. These radiators do not appear to be charged. Thus if the luminous vapor containing them is passed through wire gauze, no effect is produced on the intensity of the continuous spectrum when the gauze is charged negatively. This is quite different from the behavior of the radiators of the line spectrum which may be entirely removed by this means. It is possible in this way to obtain the continuous spectrum without any of the line spectrum appearing. As far as has been observed there are no lines or separate bands in the spectrum here described. It is, however, possible that a spectroscope better than the one at the command of the writer may show such lines. It appears probable that we are here dealing with a vapor which is intermediate between a gas and a liquid. When a gas is condensing there must be a time when two or more atoms have combined to form clusters. Such a vapor might be expected to give a spectrum intermediate between a line spectrum as given by a gas and a continuous spectrum as given by a liquid or solid. This is a fact the kind of spectrum here observed. Further work is being done on the subject and it is expected that the results will soon be published in more complete form. COLGATE UNIVERSITY, August 6, 1920 C. D. CHILD The A NEW VARIETY OF THE ROOF RAT DURING the second week of March of this year Miss Jane F. Hill, one of our students, brought to the laboratory about a dozen rats, which had been taken on her father's farm. The farm is located fifteen miles from Austin, in Travis County, Texas. Seven of these rats were cinnamon in color, the others, obviously the wild type, were gray or brownish. cinnamon color is restricted to the back and sides of the head and body, and is due to the presence of yellow pigment in the outer ends of the hairs, the pigment of the hair base probably being chocolate. In the type and mutant specimens the fur on the ventral surface, from the chin to the base of the tail, is snow white, the hairs being white from the tip to the base. We attempted to keep these rats in the laboratory, but after a few weeks they began to die. I then instructed one of our assistants to preserve the skins. Some of these were later sent to Professor W. E. Castle, who showed them to Dr. G. M. Allen. Dr. Allen identifies the species as the roof rat, Mus alexandrinus. We were anxious to establish a stock of the cinnamon rat for genetic studies, and through the kindness of Miss Hill and her family, I was able to visit the farm on July 6. During the day we captured 215 rats. Upon examination, the rats proved to be of three varieties, Mus norvegicus, Mus alexandrinus, and the cinnamon mutant. We took 61 specimens of the common Norway, 138 of the type of roof rat, and 16 of the cinnamon. Undoubtedly some of the 138 specimens of the roof rat are heterozygotes. We were fortunate enough to capture a mother and four young in one nest. Three of the litter are like the brownish-gray mother, and the third a typical cinnamon. The interesting point concerning the discovery of this cinnamon rat relates to its origin. When and how did it happen to appear on the Hill farm? With a view of answering these questions, I made a careful study of the conditions on the farm. The farm buildings where the rats are found are close together and are fairly well isolated. With the exception of one neighboring place, located about 400 yards from the Hill buildings, all other neighbors are at least a half mile distant. The cinnamon rats had not been observed prior to last Christmas, when Miss Hill saw a single animal in the grain house. From time to time others were seen in increasing numbers about the place. The rats in the farm buildings have reached such numbers that they have become very destructive. This coupled with the fact that bubonic plague has appeared in Texas, made it necessary to attempt their extermination. During the past few weeks over 1,000 rats have been killed, and among these were found a number of the cinnamon variety. From the best available data, I estimate that at present the proportion of cinnamon specimens to all others is about 15 to 200. The cinnamon rat has not been observed at any of the neighboring places, with the exception of the one located 400 yards away, where two animals were recently seen. All of the evidence points to the conclusion that this new variety arose, possibly as a mutation from Mus alexandrinus, on the Hill farm some time during the latter part of last year. This rat should furnish an opportunity for some interesting genetic studies. In a recent letter Professor Castle has called attention to the value of this material. He says: This would be very interesting genetic material for there is known to be a yellow variety of the roof rat, in addition to the black variety (Mus rattus), and if this cinnamon variety can be added to the number (with albinism, which I presume must exist among roof rats), it would be possible to work out from this material a parallel series to that which occurs in the Norway rat, possibly even a more complex series, and it would be of interest to know whether the linkage relations are the same in the two species. AUSTIN, TEXAS, July 22, 1920 J. T. PATTERSON ANOTHER CORN SEED PARASITE A FUNGUS which seems to have had yery little consideration as a parasite has recently been isolated from sweet corn seed by the writers while making a study of the internal parasites of some agricultural seeds. This fungus was frequently found in corn from a field that last year had many dwarf and distorted stalks and some barren stalks and root rot. Seeds of this corn were examined for internal parasites by treating three minutes with corosive sublimate solution according to a method which the authors have worked out and found to be very satisfactory. After this external disinfection they were planted in sterile tubes of nutrient solution on cotton. In about a week a white fungus had grown out from many of the seeds, some of which had also germinated. The roots of the seedlings were attacked by the fungus and died in about two weeks. Healthy seedlings in sterile tubes were inoculated and died in five to nine days. The pathogenicity of the fungus was further tested under more normal conditions on corn grown in pots in the greenhouse, by pouring a suspension of the spores from pure cultures around the roots and by punctures with an infected needle just above the ground. Several of the plants so infected showed the dwarfness and distortion seen in the field the previous year. Those inoculated by puncture made 19 per cent. less growth in height than the controls and the soil inoculations made 13 per cent. less. Fungous mycelium was found in the discolored tissue at the base of the stem of these infected plants and the original fungus was obtained in cultures from this diseased tissue. This fungus corresponds very well, so far as one of its methods of spore formation is concerned, with descriptions and figures of Oospora verticilloides Sacc., found on corn in Italy by Saccardo in 1877. It was extensively studied by Tiraboschi1 in an investigation of organisms in corn that might be connected with pellagra. Tiraboschi, like practically all other students of corn diseases, apparently overlooked similar work done in Russia in 1895 and 1896 by Deckenbach, who in addi1 Annali di Botanici, 1905. tion found that Oospora verticilloides was parasitic on corn. Deckenbach's work was published in Russian journals from 1896 to 1899, and after Tiraboschi's paper was published, Deckenbach reviewed his original work in Centr. Bakt., 1 Abt. Originale, 45:507–512. 1907. It is probable that this fungus has been recorded under other generic names by some writers. Cephalosporium sacchari, described by Butler as a sugar cane parasite in India, accords very well with our fungus, except that the conidia in chains were not noted by him. The distinctions between Cephalosporium, Acrostalagmus, Verticillium and similar genera are slight, and as the chains of spores of our fungus are not always easily found, this corn parasite may sometimes have been classed in one of these genera. The writers find, however, that the conidia are produced in two different ways: at first they are aggregated in small droplets at the ends of the short, sometimes verticillate, lateral branches of the erect fertile hyphæ, and later produced in long chains on the ends of the upper branches. In older cultures septate spores are occasionally found and if a Fusarium stage should develop our fungus would have to be referred to Sheldon's Fusarium moniliforme which would then better be called Fusarium verticilioides. J. B. S. NORTON, C. C. CHEN MARYLAND AGRICULTURAL EXPERIMENT STATION SCIENTIFIC BOOKS Orthoptera of Northeastern America with Special Reference to the Faunas of Indiana and Florida. By W. S. BLATCHLEY. May, 1920. Indianapolis: The Nature Publishing Co.; 8vo, 784 pages, 246 text figures and 7 plates. This work comprises a very full consideration of the 353 species and 58 varieties of Orthoptera recorded from the region covered, and is the most comprehensive treatise on this group of insects so far published in America. While prepared more especially for the tyro, this volume contains a wealth of assembled information of undoubted value to professional workers. As clearly set forth on pages 5 to 7 of the introduction, this work portrays the individual ideas of the author as to the systematic value of taxonomic characters used in classification. The conclusions reached, while not always in accord with recent usage, appear to be generally sound. The biology and anatomy of the Orthoptera are treated at some length and the parasites and other enemies of the group are discussed. Economic questions are covered and the collection and preservation of specimens fully treated. The systematic portion includes dichotomous keys to suborders, families, genera and species. The derivation of generic names is given when known and many species are figured. The illustrations are mostly taken from previously published works, but the figures are well selected for the purpose of the present manual. Under each species is a description followed by notes on synonymy, distribution, habits, etc. Citations to literature are made by reference to a chronologically arranged author's bibliography. A glossary of terms used is given and there are two indices, one of synonyms with generic assignment and one of genera and species as here treated. There is in general little to criticize in this very admirable treatise, though a critical review written by any specialist would probably point out a number of details considered open to special criticism. As is inevitable with a volume of this size a number of typographical and other errors occur. But on the whole it is a carefully prepared work, and one which. will be indispensable to all students and collectors of these insects. A. N. CAUDELL BUREAU OF ENTOMOLOGY, Manual of the Orthoptera of New England, including Locusts, Grasshoppers, Crickets, and their allies. By ALBERT P. MORSE. April, 1920. Proc. Bost. Soc. Nat. Hist., Vol. XXXV., p. 197-556, text-figures 1-99 and plates X-XXIX. Bearing a date a month earlier than the above work by Blatchley, but received nearly a month later, comes this volume, a magnificient treatise on the orthopterous insects of New England. An introduction to the literature of New England Orthoptera is given and the anatomy and biology of this group of insects are discussed at some length. The distribution of the species within the region covered is considered and there are several pages devoted to a consideraton of the economic relations of the Order, including discussions of parasites and other enemies. Collecting and preserving are fully treated and there are keys to genera and species and higher groups. Under each family are notes on habits, etc., and under each species are references to the more important literature on the species and its synonyms. There are also notes on occurrence and, usually, brief descriptions. One hundred and thirty-two species are recorded, sixteen of which are considered adventive. There is no bibliography of works cited. The structural details of a large proportion of the forms treated are figured, and many are more fully illustrated, some in colors. There are also a number of reproduced photographs showing certain characteristic habitats of Orthoptera. Three colored plates and a few other illustrations are original, but most of the figures are reproduced from previously published works. An accented list of scientific names, a glossary, and an index conclude this most excellent manual. BUREAU OF ENTOMOLOGY, A. N. CAUDELL U. S. DEPT. OF AGRICULTURE slight modifications, in part suggested by Dr. Robert Chambers, the two-needle model formerly made in the Fowler shops of the University of Kansas. The principal advantage of the stand as previously stated by Dr. Chambers1 is that the dissecting apparatus is attached to a shelf independent of the microscope and consequently the latter may be shifted to various positions with reference to the dissecting apparatus. Also another microscope or binocular microscope may readily be substituted without the necessity of the assistance of a machinist to construct a shelf on each microscope used. SPECIAL ARTICLES A STAND FOR THE BARBOUR MICRODISSECTION APPARATUS THE following is a description of a stand devised by the writer and Mr. F. H. J. Newton, mechanician at Wesleyan University, for use with the Barbour microdissection apparatus. The dissecting apparatus was also made by Mr. Newton, who reproduced with FIG. 1. The drawing here shown omits for simplicity certain details of the dissecting apparatus as it has been figured elsewhere.1 The thumb screw on the right side which is at1 Chambers, R., Biological Bulletin, Vol. 34, 1918. tached at G is omitted from the drawing in order to show parts otherwise concealed. The essential parts are the platform and shelf. The platform, A, which measures 9 by 7 inches is supported on legs having leveling screws, B, and has a portion cut out, C, on the longer side similar in form to the open space between the sides of the horseshoe base of a microscope. This opening is to admit light from an ordinary microscope mirror suspended beneath the stand by a jointed arm, J, allowing lateral motion and which is in turn attached to a horizontal rod sliding back and forward in a tube on the under surface of the platform. On the front edge of the platform bridging the light opening is the shelf, E, supported by two pillars, D. The dissecting apparatus is clamped to this shelf by the screw, F. The microscope may be firmly secured to the platform by the clamps, H, and holes are drilled in the platform to accommodate various positions of the microscope, but frequently the use of the clamps is unnecessary. Dr. Chambers has suggested that I call attention to a useful improvement of his own dissecting apparatus introduced by E. A. Thompson, of Amherst, Mass. Fine springs placed around the screws which move the needle carriage as at I in the figure prevent lost motion and thus steady the initial motion of the needle which is a marked advantage in the finer work. WESLEYAN UNIVERSITY H. B. GOODRICH GASTRIC RESPONSE TO FOODS1 IX. THE INFLUENCE OF WORRY ON GASTRIC THE study of the influence of emotional strain on digestion in man offers some difficulties due to the fact that the emotions can not be readily controlled, nor are the subjects of extreme emotion readily amenable to experimentation. We were, however, able to obtain an interesting illustration of the pro 1 The expenses of this investigation were detrayed by funds furnished by Mrs. M. H. Hender son. found effect of mental anxiety on gastric digestion in the case of a first-year medical student who had previously served as a subject of gastric tests and whose stomach had been found entirely normal. This man was given one hundred grams of fried chicken on the morning of an important examination in chemistry, and was asked to write out his answers during the course of the test. He was plainly worried over the outcome of the examination and of his year's work. The resultant effect upon gastric digestion in prolonging evacuation for over two hours, with high intra-gastric acidity is charted in the figure. The same chart gives the normal digestion curve for fried chicken on this subject as obtained a week later under the best mental conditions. The experiments were carried out by withdrawing samples from the stomach of the subject with the Rehfuss stomach tube at fifteen-minute intervals until the stomach was empty. The specimens were analyzed for total acidity and free hydrochloric acid and results expressed as c.c. of N/10 alkali required to neutralize 100 c.c. of sample. 2 Fishback, Smith, Bergeim, Lichtenthaeler, Rehfuss and Hawk, Am. Jour. Physiol., 1919, XLIX., 174, and later communications. |