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THE confirmation by X-ray data1,2of C2, the A 288-residue cage structure proposed for the insulin molecule3, makes it of interest to consider the nature of the cyclol bond, upon the postulation of which this structure and the cyclol theory of protein structure in general4depend.The making and breaking of a cyclol bond between an NH group of a polypeptide chain and a CO group of the same or of another polypeptide chain, requires only the migration of an H atom thus:

SINCE 1961 when the oral poliomyelitis vaccines were first made available for general use in the United States, scattered cases of paralytic disease have occurred in association with these vaccines. Many of the cases have been clinically indistinguishable from poliomyelitis. Epidemiologically, the pattern of their occurrence has raised the possibility that some may have been caused by the vaccine.In 1962 when the existence of this problem was first appreciated, the Surgeon General of the Public Health Service convened a special advisory committee which met on a number of occasions between August and December. The Committee reviewed in detail reported cases of paralytic disease occurring within a period of 30 days following ingestion of the oral poliomyelitis vaccines. The Committee concluded that 18 cases of paralytic poliomyelitis were "compatible with the possibility of having been induced by the vaccine." Of these, 11 followed type III vaccine and 7 followed type

FIVE AND ONE-HALF YEARS AGO, when the Salk vaccine first became available, some epidemiologists, including myself, were hopeful that poliomyelitis could rapidly be eradicated. Since then, its incidence has declined, largely because of the use of this vaccine. But, poliomyelitis seems far from being eradicated. The dreamed-of goal has not been achieved. In fact, many students of the problem question that eradication of poliomyelitis infection with inactivated vaccine is a scientifically tenable concept.Soon, a basically new type of poliovirus immunization—the orally administered live virus vaccine— will enter the picture. Dr. Albert Sabin, one of the developers of oral vaccine, is now calling for eradication of poliomyelitis, arguing that the oral vaccine makes this scientifically possible. It is pertinent, therefore, at this symposium, to review the experience of the past 5 1/2 years, from both the practical and scientific points of view. It may be worthwhile to examine the reason

Laboratory experiments have been devised to make measurements of the visibility of light signals under conditions essentially similar to those encountered by the aviator or the navigator. Data have been collected on the direct visibility of flashing-point sources of light of different colors, flash lengths, and intervals, against different backgrounds. The time taken to locate a visible beacon was studied as a function of the beacon intensity and frequency of flashing. The threshold candlepower required for visibility of a point source against a background is given by an empirical equation. Colored point sources were not found to be useful except in the case of red lights with background intensities above moonlight. For an airplane approaching a beacon it is advantageous to use frequencies of flashing as high as 12 to 30 per min., although with exceptionally clear atmosphere, lower frequencies may be better. In a study of the visibility of flashes of diffused light superimposed on a steady white background, white-light flashes gave the best results. A selective differential photoelectric receiver is described which detects signals of modulated diffused light of low intensity. This sensitivity is independent of the steady background brightness up to 100 times moonlight, and is from 6 to 13,000 times as great as that of the eye in the range of background intensity from darkness up to moonlight. The greatest difficulty in transmission of light signals through fog lies in the loss of advantages of the point source. Dense fog may increase the distances at which diffused-light signals may be detected. The range depends to a considerable extent on the reflectivity of the ground. A theoretical treatment of the diffusion of light through fog, based on the scattering of the light rays by fog particles, indicates that airplanes can be guided through fog at distances of several miles by means of diffused modulated light acting on a differential photoelectric receiver.

The radiation of energy from a thoriated tungsten filament and the absorption of the energy radiated from the surrounding bulb have been measured by a method which eliminates difficulties arising from cooling effects of the leads. For a filament at a uniform temperature TF in a bulb at temperature TB the net radiation W in watts cm^−2 is the difference between the outgoing radiation WR and the absorbed radiation WA. For values of TF from 225° to 580°K and TB from 77° to 473°K logW_R=83.7105−100+5.332logT_F,logW_A=83.7105−100+4.462logT_B+0.87logT_F.The resistivity R_0 in this same range is given by logR_0=91.7123−100+1.23logT_F.The characteristics, current, voltage, resistance, and energy radiated as functions of temperature are tabulated.

When should an historian analyze the assumptions which underlie his work, and when, if ever, is it incumbent on him to include in his work a discussion of the beliefs and procedures which have influenced his treatment of a subject? Recently historians, and in particular English medievalists, have been criticized for their anarchic empiricism; yet willingness to utilize any approach which promises concrete results, regardless of an integrated theoretical justification, is an attitude by no means limited to history but characteristic of many fields of detailed investigation in the natural and social sciences. By their fruits, as appraised by experts in the same field, shall their works be judged. There are times, however, when a broad historical subject is so narrowly treated that the result is tantamount to a philosophical statement, a statement, however implicit, that there is but one way of gaining valid knowledge of of men's past actions. We may then feel that the historian ought to have justified his procedure more explicitly, and we may be provoked to analyze and criticize the work, not for what has been said in it, but for what has not. This is especially true when the contrast between the dimensions of the subject and the limitations of a particular historian's vision throw his approach into high relief and incite the reader to examine the historian's conception of history. The English Jewry under Angevin Kingsby H. G. Richardson is such a book because of its tone of certainty as to the proper path of history and because its subject cannot be domesticated to the calm conventions of professional habit.

The ordinances on the Jews of 1223 and 1230 are generally described as the beginning of effective general legislation by the Capetians, yet agreement on the constitutional importance of the ordinances has not produced agreement on their precise meaning and significance. On the one hand, historians such as Esmein, Viollet, Declareuil, Chénon, Perrot, Fawtier, and Olivier-Martin, who followed Flammermont and Luchaire's analysis of royal legislative power, have held that all the provisions of both the 1223 and the 1230 ordinance bound both those who had consented and those who had not, and were applicable throughout the kingdom. On the other hand, an older view stemming from Brussel and Petiet, followed hesitantly by Glasson, and most recently advanced by Petit-Dutaillis, has maintained that, although the 1230 ordinance was applicable in its entirety throughout the kingdom, the ordinance of 1223 either applied in its entirety only to those who had consented to it, or else contained only one provision applicable to those who had not sworn to observe it. This disagreement results partly from ambiguities in the texts, but it is also a result of a failure to set the ordinances in the context of their avowed purposes.

Since Jan. 1, 1937 reports on the use of concentrated antipneumococcus serum have been submitted on a uniform record to the New York State Department of Health by physicians employing serums produced or purchased and distributed by the Division of Laboratories and Research.1 The questions on that form are concerned, so far as possible, with objective data, so that the effect of interpretation by the reporting physician is minimized. Through a follow-up system, complete reports were obtained in practically every case.2Early study of the material so collected brought to light a number of immediate reactions following intravenous serum therapy which were associated with severe circulatory collapse and which did not seem to be related to protein hypersensitivity in the usual sense. It was recognized that this impression was based on reports which had the disadvantage of containing second hand information of varying degrees of accuracy. In order