INTERFERENCE BETWEEN THE INFLUENZA VIRUSES : II. THE EFFECT OF VIRUS RENDERED NON-INFECTIVE BY ULTRAVIOLET RADIATION UPON THE MULTIPLICATION OF INFLUENZA VIRUSES IN THE CHICK EMBRYO.

Influenza A or influenza B virus rendered non-infective by ultraviolet radiation was found to be capable of producing interference with the multiplication of active influenza viruses in the chick embryo. Certain temporal and quantitative relationships affecting the interference phenomenon with this host-virus system were studied. An hypothesis of the mechanism of interference between the influenza viruses is proposed and discussed.

INTERFERENCE BETWEEN THE INFLUENZA VIRUSES : I. THE EFFECT OF ACTIVE VIRUS UPON THE MULTIPLICATION OF INFLUENZA VIRUSES IN THE CHICK EMBRYO.

Reciprocal interference between influenza A, influenza B, and swine influenza viruses has been demonstrated in the chick embryo. Certain temporal and quantitative factors which influence the production of interference in this host-virus system have been studied. The implications of these observations in relation to the mechanism by which interference is produced are discussed.

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 Circulating specific complement-fixing and neutralizing antibodies not present in sera withdrawn during the acute phase of illness were demonstrated in sera obtained during convalescence.

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.

THE LS-ANTIGEN OF VACCINIA : III. PHYSICAL-CHEMICAL PROPERTIES OF LS-ANTIGEN AND SOME OF ITS DEGRADATION PRODUCTS.

Studies on LS-protein, the soluble double antigen of vaccinia, and on the degradation products L'S and L''S' have been made with electrophoresis and in the analytical ultracentrifuge. LS, which is homogeneous electrically and in the ultracentrifuge, has an isoelectric point at pH 4.8.

THE LS-ANTIGEN OF VACCINIA : II. ISOLATION OF A SINGLE SUBSTANCE CONTAINING BOTH L- AND S-ACTIVITY.

Virus-free filtrate, obtained from suspensions of vaccine virus-infected dermal pulp of rabbits and rich in the soluble substances of vaccinia, was shown to contain four distinct components in electrophoresis experiments. Electrophoretic and serological observations served as a guide in developing a method for separating these components from one another. This method depended upon changes in the solubilities of the components with alterations of pH.

ELECTROPHORETIC STUDIES ON ELEMENTARY BODIES OF VACCINIA.

Electrophoretic studies were made on vaccine virus, collodion particles, and glass particles suspended in 0.01 molar buffer solutions at pH 7.9, in which the moving boundary method was used.

ULTRACENTRIFUGATION STUDIES ON THE ELEMENTARY BODIES OF VACCINE VIRUS : I. GENERAL METHODS AND DETERMINATION OF PARTICLE SIZE.

Ultracentrifugal studies on the CL dermal strain of vaccine virus indicate the following characteristics of the elementary bodies:- 1. A stable suspension of Paschen bodies in a dilute buffer solution of pH 6.2 to 8 sediments with the formation of a characteristic primary boundary which consistently shows a spread of approximately 14 per cent.

THE ABSENCE FROM THE URINE OF PERNICIOUS ANEMIA PATIENTS OF A MOSQUITO GROWTH FACTOR PRESENT IN NORMAL URINE.

Extracts prepared from the urine of normal persons or patients with aplastic anemia or leukemia contain a substance, possibly flavine or a flavine compound, which under suitable conditions of test enhances the growth of larvae of the mosquito, Aëdes aegypti. This substance is lacking, or is present in much smaller amount, in extracts from the urine of pernicious anemia patients showing symptoms of the disease. Extracts from the urine of the same patients after adequate treatment contain as much of the substance as normal urine extracts.

THE SUSCEPTIBILITY OF SWINE TO THE VIRUS OF HUMAN INFLUENZA.

Swine inoculated intranasally with human influenza virus alone develop an ill defined, mild, and usually afebrile illness of short duration. At postmortem the anterior lobes of the lungs of such animals contain scant, scattered areas of lobular atelectasis. Transmission of the virus for 5 serial passages through two groups of swine failed noticeably to enhance its pathogenicity for this species.

IMMUNOLOGICAL AND CHEMICAL INVESTIGATIONS OF VACCINE VIRUS : II. CHEMICAL ANALYSIS OF ELEMENTARY BODIES OF VACCINIA.

Washed elementary bodies obtained from dermal vaccine virus contain ash, carbohydrate, fat, and nitrogen a part of which is undoubtedly in the form of protein. These components are similar to those found in bacteria and other substances of protoplasmic origin.

PERIVASCULAR REACTIONS IN LUNG AND LIVER FOLLOWING INTRAVENOUS INJECTION OF STREPTOCOCCI INTO PREVIOUSLY SENSITIZED ANIMALS.

Intravenous inoculation of small doses of non-hemolytic streptococci into previously sensitized rabbits is usually followed by the appearance of perivascular cellular aggregates in lung and liver. The characteristic cell in these aggregates is moderately large, with vesicular nucleus, prominent nucleoli, clumped chromatin, and basophilic cytoplasm. In addition, the lesions contain small lymphocytes and granulocytes.

THE EQUILIBRIA BETWEEN NATIVE AND DENATURED HEMOGLOBIN IN SALICYLATE SOLUTIONS AND THE THEORETICAL CONSEQUENCES OF THE EQUILIBRIUM BETWEEN NATIVE AND DENATURED PROTEIN.

The denaturation of hemoglobin by salicylate in neutral solution is completely reversible. There is a mobile equilibrium between native and denatured hemoglobin in neutral salicylate solution. The higher the salicylate concentration the greater is the percentage denaturation.

THE EQUILIBRIUM BETWEEN ACTIVE NATIVE TRYPSIN AND INACTIVE DENATURED TRYPSIN.

There is a mobile equilibrium between the native and denatured forms of trypsin which depends on the concentrations of acid, alkali, and alcohol and on the temperature. The heat of denaturation in 0.01 N hydrochloric acid calculated from the effect of temperature on the equilibrium constant is -67,600 calories per mole.

THE ESTIMATION OF ACTIVE NATIVE TRYPSIN IN THE PRESENCE OF INACTIVE DENATURED TRYPSIN.

Inactive denatured trypsin changes into active native trypsin in the protein solutions which have been used to estimate tryptic activity. If the digestion mixture, however, is alkaline enough and contains enough urea this change does not take place. Such a digestion mixture can be used to estimate active native trypsin in the presence of inactive denatured trypsin.

THE ESTIMATION OF TRYPSIN WITH HEMOGLOBIN.

The formation from hemoglobin of split products not precipitable by trichloracetic acid is taken as a measure of tryptic activity. The split products are estimated colorimetrically. Many measurements of tryptic activity can be made in a short time and different samples of hemoglobin yield the same results.

THE EFFECT OF DENATURATION ON THE VISCOSITY OF PROTEIN SYSTEMS.

The viscosity of a protein solution is increased by the denaturation of the protein. This is true both when there is the formation of protein aggregates which occlude water and when there is no aggregation. Under certain conditions, as a result of the aggregation following denaturation, a solution containing only one per cent of protein may be converted into a clear gel.

PROTEIN COAGULATION AND ITS REVERSAL : SERUM ALBUMIN.

1. It is possible to prepare crystalline, soluble, heat-coagulable serum albumin from coagulated serum albumin. 2.