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tial inhibition (1+ acetone insoluble, 2+ cholesterinized antigen). The same serum was kept in a refrigerator for four days more, and tests on both were negative, which does not confirm the opinion of Thompson that heated serum tends to become positive when kept. This patient, after receiving quinine for five days, gave a negative complement fixation test on fresh-heated serum. He was at that time free of parasites. A careful inquiry into his history and careful physical examination by competent clinicians revealed no evidence of syphilis. Several later tests on this patient were negative. It is believed that this reaction was not due to faulty technique, as it is extremely unlikely that two mistakes would be made in one run of tests, nor, if made, that they would occur in tubes in widely separated positions in the rack. The same series of tests carried cleancut positives and negatives in addition to the controls, and tests on a group of syphilitic patients at varying stages of intensive hospital treatment and showing the degree of inhibition of hemolysis expected at their respective treatment stages.

Another patient, with a history of initial malaria infection in 1921, has had numerous recurrences, with a record of four negative Noguchi reactions at various naval laboratories. In all these laboratories the complement fixation technique is the same as that employed in this laboratory, and their antigen and amboceptor were produced here. One of the negative tests was performed here on blood taken a few hours after a chill in a previous attack. On blood taken within 30 minutes of the onset of a chill, showing very numerous parasites of benigh tertian malaria, a 3+ reaction with acetone insoluuble antigen and complete inhibition (4+) with cholesterinized, was the result. Blood taken 22 hours after the paroxysm gave a 2+ and 3+ reading. Both serums were kept in the refrigerator for four days and tested again with negative reactions. This patient also gave no evidence of syphilis on careful examination. Serum taken after five days of quinine gave a 1+ and 3+ reaction.

So excluding two known syphilitics with malaria, there have been enly two positive complement fixation tests in 32 patients. As most of the patients had more than one test the actual number of Noguchi tests were approximately 55.

One interesting clinical observation was that at least two of the patients having malaria, had recently completed a course of arsenical treatment for syphilis, without eradication of the Plasmodium vivax. This was evident from the recurrence of symptoms of malaria at a season and location precluding new infection.

In reviewing the laboratory records, there were recorded 38 complete blood counts made at the time of finding the malaria parasites.

A few of the counts showed very marked increase in the percentage of large mononuclear cells, but the average of the count was as follows:

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There is possibly a slight increase in the. percentage of large mononuclears but the count tends to confirm the recent report of Swan (15) in which he considered a large mononuclear increase as not constant during the active stage of malaria.

Our records of complement fixation tests seemed to confirm the opinion that a test conducted according to a standardized techinque on the serum of malaria patients will be negative in the absence of syphilis. However the last two patients, appearing while this paper was in preparation, and showing at least partial inhibition of hemolysis in more than one portion of serum necessitates the conclusion that occasionally serum taken during active schizogony may yield a positive Noguchi test, but that it is very uncommon. In view of the two positives in cases of treated syphilis, both with negative Noguchi's test prior to the onset of malaria, we feel that we have additional evidence that a positive Noguchi in malaria is due to syphilis in the great majority of cases. Of course the impropriety of doing a Noguchi test on a patient during his active malaria as a diagnostic test should rule out any improper assumption of syphilis as a result of the very rare positive test.

CONCLUSIONS.

1. Large mononuclears are slightly if at all increased in the active stage of malaria.

2. Careful technique will eliminate a number of the positive complement fixation tests in malaria.

3. Rarely there is a partial inhibition of hemolysis in serum taken during active schizogony.

4. Because of this rare positive, no attempt to diagnose syphilis by a complement fixation test in a malaria patient should be made till after the peripheral circulation has been freed of a demonstrable parasites by quinine.

5. Patients with treated syphilis and a negative Noguchi may show a weakly positive reaction if their serum is taken during a malarial paroxysm, but the majority will not.

REFERENCES.

(1) Wagner-Jauregg-Jour. Nerv. and Ment. Dis., May, 1922.

(2) S. I. de Jong and A. Martin-Presse méd., 25: 617-October 25, 1917. (3) S. I. de Jong-Bull. et mên. Soc. med. d. hôp. de Paris, 1-10-19-43. No. 1.

(4) J. Gordon Thompson and C. H. Mills-Lancet, 1:782-May 10, 1919. (5) J. H. St. John-Am. Jour. Trop. Med., 1: 319-September, 1921. (6) Maj. J. Pratt Johnson-Jour, Path, and Bacteriol, 24; 145-1921. (7) Craig, Chas.-" The Wassermann Test"-1921, 2d edition.

(8) W. D. Sutherland and G. C. Mitra. Indiana Jour. Med. Research, 2, 984-989.

(9) F. H. Hewerth and W. A. Kop-Jour. Hyg. 19: 277-January, 1921. (10) Wassermann and Lange (Kolle and Wassermann VII, p. 1007, Handbuch Pathol. Mikroorg).

(11) Schoo-Nederlandsche Tijdschrift v. Geneeskunde, p. 295-1910.

(12) Zuchucki-Berliner klin. Wochenschrift, p. 1716-1913.

(13) DeHaan Geneeskundig Tijdschrift v. Ned. Indie, p. 737-1913.

(14) Meyerstein-Munchen Med. Wochenschrift, p. 366-1917.
(15) John M. Swan-Am, Jour. Trop. Med., 2: 253-July, 1922.

ILLUMINATION OF DENTAL OFFICES ASHORE AND AFLOAT.

By H. E. HARVEY, Lieutenant Commander, Dental Corps, United States Navy.

The very unfavorable conditions of lighting under which dental work is expected to be performed aboard ship has caused the writer to give considerable thought and attention to the subject. When it is recalled that portholes on shipboard may be circles 11 inches in diameter, cut in the side of the ship, and that it is through one of these, or under exceptionally favorable circumstances two of them, that daylight is obtained, some idea may be had of the limited amount of natural illumination available. Electric lights, of course, are available and it is to the disposition of these that attention was directed.

Part of the service of naval dental officers is on shore, and lighting conditions in the offices ashore are found to be without uniformity and in many cases very unsatisfactory. The problem, therefore, was to formulate if possible an arrangement of light which could be used with equal advantage afloat or ashore.

In 1917 an inspection of some of the better class dental offices in New York and Brooklyn, as well as inquiries at dealers both dental and general, elicited the fact that, with one exception, but little attention had been given the subject of proper illumination for dental work.

On shipboard about that time all living quarters were painted with white enamel with the idea apparently of making the most of the light rays present through reflection. This has happily been

discontinued as the effect day in and day out was to produce a glare which to say the least was not restful to the eyes. Recommendations of certain medical officers have been followed and interiors are now finished in flat paint with a slight tint, and this, combined with shaded light and indirect illumination, has proven very satisfactory. We are told that the light intensity outdoors at noon on a clear day of June will average about 9,600 foot-candles and in December under the same conditions about 4,300 foot-candles. In contrast to this the illumination or average light of our workshops at night will seldom exceed 5 or 6 foot-candles. By some it is believed that an office can be too well lighted, with injurious results, but apparently the truth is that harm seldom or ever comes from too much illumination. Glare, not light, in practically all cases is the damaging factor. As light increases the ciliary muscles of the eye contract, lessening the aperture of the pupil. If, however, the light is caused by glare a much greater contraction occurs than is justified by the actual intensity of the illumination present. This explains why, when fine work is attempted in the presence of glare, a further accommodation is necessary which is not consistent with the amount of general illumination. Under such circumstances removal of the vision from the work causes a contraction of the ciliary muscles, which are again relaxed as work is resumed, and this seesaw back and forth is thought to be responsible to a large degree for eyestrain. In other words, fatigue here, as elsewhere, is caused by the presence of poisonous waste products which are produced faster than they can be physiologically removed from the muscles. Corpuscular disintegration of the blood is said to be responsible for the pain which persists in muscles for several days after unusual exercise; logically the same condition may be present in the intrinsic eye muscles, with the added factor that the feeling of discomfort is usually not definitely localized.

As will be seen above, the human eye is perfectly comfortable outdoors with a light intensity more than a thousand times greater than that generally used by people in the evening when they read or work at home or in the office. Daylight is the easiest of all light on the eyes, and the reason is that day light reaches us in a high state of diffusion. In this connection it has been suggested that window roller shades should be of translucent material such as oiled écru Holland, which, while permitting access of light, will diffuse and soften the rays of the sun. Opaque shades will diminish illumination without diffusion.

Efforts have been made to secure lighting results wherein shadows are eliminated. This we are informed is a mistake, for it is the shadow which produces the relief, causing contrasts and the object

to stand out. Stereoscopic work, of interest to dentists in radiography, it will be recalled, is one of definite shadows.

Lighting engineers have found that it is injurious to have strong light directed to the cutting point of tools and to the top of workbenches, while all around the operative a semidarkness prevails. Excessive lights on spots causes eyestrain and poor vision of surrounding areas. Such a lighting arrangement, as the eye shifts from light to dark and vice versa, causes an undue pupillary reflex which is conducive to strain if continued over a period of time. In a large percentage of cases in which glasses are worn the necessity for them has arisen from the kind of light under which work has been done. Our traditional dental textbooks, as recalled, recommend a north light. This recommendation, however, in the opinion of the writer is open to discussion and should not be accepted on historical grounds, particularly during the winter months of early darkness. A ship at anchor swings with the tide, and the reason for disputing the advisability of using north light is that experience has demonstrated much less fatigue and eyestrain when working on the side of the ship which swung to the sun. The other side of the ship enjoys a more even light, which is claimed as the merit for the north light, but it does not seem to be of sufficient intensity. This is especially noticeable toward the close of the day when fatigue is present.

Various types of lights, projectors, and lamps have been experimented with and indirect illumination for fine work is considered not to be economical from the standpoint of efficiency. A competent authority stated that it was his opinion that to secure illumination of a cavity with a red lining such as the mouth, ten times the intensity of light is needed to produce that equal to the surface surrounding the orifice. Such a disposition and diffusion of light would seem to answer the requirements; that is, that the interior of the mouth be illuminated with a light of sufficient intensity to make the illumination approximately equal to that present on the orifice and in the well-lighted room in general. In other words, no undue pupillary reflex should be induced when directing the vision in the mouth and without. A dental-operating light, such as the Rhein type, wherein a cluster of lights is suspended in front and to the left of the patient, or one of the Bosworth type, a single lamp of brilliant intensity, would seem to be deficient in that general illumination only is present, the end result being that the operator is endeavoring to work in a field considerably darker than the surface about the orifice and the surrounding room, manifestly an improper proceeding. The objection to this type also exists, viz, that a constant glare is present both to the eyes of the patient and operator. As the latter

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