THE EFFECTS OF ROENTGEN RAYS ON CELL-VIRUS ASSOCIATIONS : FINDINGS WITH VIRUS-INDUCED RABBIT PAPILLOMAS AND FIBROMAS.

The virus-induced papillomas of cottontail as well as domestic rabbits regress completely within a few weeks when exposed to 5,000 r of x-ray irradiation. The x-rays do not immediately kill the papilloma cells, but lead to death by inhibiting cellular division and producing pathological changes in the cells which then continue to differentiate. The virus associated with the growths, however, not only persists in undiminished amount during regression, but often an increased yield of it can be obtained on extraction.

THE OXIDATION OF p-AMINOBENZOIC ACID AND ANTHRANILIC ACID BY SPECIFICALLY ADAPTED ENZYMES OF A SOIL BACILLUS.

1. A soil bacillus has been isolated capable of developing specific adaptive enzymes which oxidize PABA apparently to carbon dioxide, water, and ammonia. A few related compounds which, however, do not give the diazo reaction are similarly attacked.

THE STABILITY OF VARIOLA VIRUS PROPAGATED IN EMBRYONATED EGGS.

After 24 transfers in embryonated eggs a strain of variola virus (Chinese) was established in the testis of the rabbit and maintained for 11 passages at intervals of 7 days. Residence in the rabbit testis was not accompanied by any significant alteration in the species identity of the virus. A second strain of variola virus (Minnesota) was transferred 180 times in embryonated eggs with no apparent change in its behavior.

NATURE OF THE ACTION CURRENT IN NITELLA : V. PARTIAL RESPONSE AND THE ALL-OR-NONE LAW.

When a stimulus arrives before recovery is complete there may be no response or only a partial response. A typical response appears to involve an immediate loss of potential at the inner protoplasmic surface but not at the outer surface. As long as recovery is incomplete only a part of the total potential is located at the inner protoplasmic surface and the loss of this part of the total potential can cause only a partial response; i.

AN OUTBREAK OF PSITTACOSIS IN PIGEONS, INVOLVING THE PRODUCTION OF INCLUSION BODIES, AND TRANSFER OF THE DISEASE TO MAN.

An epizootic disease in pigeons associated with atypical pneumonia in two persons handling the birds has been studied. Most of the observations made during the work were consistent with the idea that we were dealing with an infection caused by a member of the psittacosis-lymphogranuloma venereum group of viruses. The outbreak was peculiar, however, in that tissues of the diseased pigeons contained many intranuclear inclusions and that the viruses isolated from these birds produced both intranuclear inclusions and elementary bodies in the cytoplasm of cells of chorio-allantoic membranes of the developing egg.

TYPING GROUP A HEMOLYTIC STREPTOCOCCI BY M PRECIPITIN REACTIONS IN CAPILLARY PIPETTES.

A method is described for performing type-specific anti-M precipitin tests on group A hemolytic streptococci in 1 mm. capillary pipettes. These tests require so much less precipitating serum than was formerly used that the method now seems to be practical.

SYNERGISTIC ACTION OF HEMOPHILUS INFLUENZAE SUIS AND THE SWINE INFLUENZA VIRUS ON THE CHICK EMBRYO. II.

Blood cultures of embryos killed by the synergistic action of swine influenza virus and Hemophilus influenzae suis are consistently negative, and embryos infected with swine influenza virus may be killed both by filtered extracts of frozen and dried Hemophilus and by suspensions of heat-killed bacteria. The addition of Hemophilus to the chorioallantoic membrane of embryos infected with swine influenza virus causes the virus to spread from the membrane to the allantoic fluid and embryo. This spreading effect also obtains when a purified preparation of hyaluronidase is used instead of Hemophilus, but it is unaccompanied by a comparable increase in mortality.

THE INFLUENCE OF AGE OF HOST AND TEMPERATURE OF INCUBATION ON INFECTION OF THE CHICK EMBRYO WITH VESICULAR STOMATITIS VIRUS.

Chick embryos after 7 days of incubation were found to be much more susceptible to infection with vesicular stomatitis virus than were 10 day embryos. They had a 100 per cent mortality and were very suitable for titrations of the virus. The rate of increase of virus in 7 and 10 day embryos was studied.

THE INFLUENCE OF BIOTIN UPON SUSCEPTIBILITY TO MALARIA.

Biotin-deficient chickens and ducks developed much more severe infections with Plasmodium lophurae than did non-deficient control animals. While a very mild degree of biotin deficiency sufficed to increase susceptibility, even an extreme degree of pantothenic acid deficiency had no effect. Biotin deficiency also increased the susceptibility of ducks to P.

VENEZUELAN EQUINE ENCEPHALOMYELITIS IN MAN.

A filterable agent was isolated from the blood and from washings of the upper respiratory passages of a young laboratory worker during a mild, acute, febrile illness. This agent was identified as a strain of Venezuelan equine encephalomyelitis virus. Circulating specific complement-fixing and neutralizing antibodies not present in sera withdrawn during the acute phase of illness were demonstrated in sera obtained during convalescence.

PACEMAKERS IN NITELLA : III. ELECTRICAL ALTERNANS.

An electrical impulse traveling along a Nitella cell may produce a complete or a partial response. The two kinds of response may occur in regular alternation. The partial response varies greatly and may be so far reduced as to appear as a local thickening in the upstroke of the action curve, usually accompanied by a more or less pronounced hump.

BIOCHEMICAL STUDIES ON THE VIRUS AND THE INCLUSION BODIES OF SILKWORM JAUNDICE.

Silkworm jaundice virus is stable only between pH 5 and about pH 9. The fact that polyhedral bodies retain virus activity after exposure to hydrogen ion concentrations as high as pH 2 is regarded as being due to the protection of virus occluded within the bodies. Further evidence on this point is furnished by experiments on the activity of the polyhedra when treated with antiformin-formalin and when treated with 1 per cent sodium dodecyl sulfate.

THE IMMUNOLOGICAL PROPERTIES OF THE HETEROPHILE ANTIGEN AND SOMATIC POLYSACCHARIDE OF PNEUMOCOCCUS.

1. The lipocarbohydrate or F polysaccharide derived from a rough variant of Type I pneumococcus (I R) is antigenic in rabbits and gives rise to precipitins and sheep cell hemolysins. The somatic or C carbohydrate on the other hand is not antigenic.

A METHOD FOR THE DETERMINATION OF THE BLUE DYE T-1824 IN PLASMA.

A method for the estimation of the concentration of the blue dye, T-1824, in plasma has been developed. The method is based on the fact that the dye can be reduced to a colorless compound by Na(2)S(2)O(4), in alkaline solution. The extinction coefficient is determined under specified conditions before and after reduction of the dye.

FURTHER STUDIES ON THE SURVIVAL AND DEVELOPMENT IN VITRO OF A MALARIAL PARASITE.

The survival of Plasmodium lophurae in vitro is favored by the presence of calcium pantothenate (0.02 mg. per ml).

INDUCED RESISTANCE OF THE CENTRAL NERVOUS SYSTEM TO EXPERIMENTAL INFECTION WITH EQUINE ENCEPHALOMYELITIS VIRUS : II. SEROTHERAPY IN WESTERN VIRUS INFECTION.

Under none of the experimental conditions here described was treatment of the infection induced by the virus of Western equine encephalomyelitis in mice and guinea pigs with specific hyperimmune rabbit serum effective if begun after the onset of signs of encephalitis. In mice, after intracerebral inoculation of virus, serum was ineffective when given even before that stage. After peripheral introduction of virus in guinea pigs the disease was completely arrested in certain animals by single or multiple doses of antiserum if treatment was begun within 24 to 48 hours after virus inoculation.

ISOLATION OF CHROMATIN THREADS FROM THE RESTING NUCLEUS OF LEUKEMIC CELLS.

1. A method for the separation of chromatin threads from the resting nucleus of leukemic cells has been described. 2.

THE COURSE OF EXPERIMENTAL INFECTION OF THE CHICK EMBRYO WITH THE VIRUS OF EQUINE ENCEPHALOMYELITIS.

The titration curve for the virus of Eastern equine encephalomyelitis inoculated into the 10 day old chick embryo shows that the maximum increase in virus content continues until shortly before the generalized destruction of the embryo is apparent. This is followed by a stationary phase. Histological studies of infected embryos fail to demonstrate selective tissue destruction, and titrations show the virus to be distributed throughout the egg, although concentrated in the embryo.

MAMMALIAN RED CELLS AS A SOURCE OF "SMALL PARTICLES".

1. Small particles essentially similar to those previously isolated from other tissues have been isolated from mammalian red blood cells (horse blood). 2.

STUDIES ON THE NATURE OF THE VIRUS OF INFLUENZA : II. THE SIZE OF THE INFECTIOUS UNIT IN INFLUENZA A.

The pathogenic agent of influenza A has been sedimented from infected extra-embryonic fluids of the developing chick, embryo by ultracentrifugation. Material so obtained contains two fractions resolvable in the analytical centrifuge cell. The first, a homogeneous fraction, showed a sedimentation constant S(20) = 20 to 31 x 10(-13).

ORAL PAPILLOMATOSIS OF RABBITS: A VIRUS DISEASE.

Papillomas occur frequently on the oral mucosa of domestic rabbits procured in the metropolitan area of New York. They are small and benign, and are situated mostly on the under side of the tongue. A filtrable virus can be extracted from them with which growths can be reproduced in the oral mucosa of several species of rabbits and hares but which fails to cause lesions when inoculated into other rabbit tissues and into the oral mucosa of other species.

THE LS-ANTIGEN OF VACCINIA : IV. CHEMICAL ANALYSIS OF LS AND THE EFFECT OF CHYMOTRYPSIN ON LS.

Pure LS-antigen of vaccinia contains 15.8 per cent N and 50.6 per cent C.