A STUDY OF THE INHIBITION OF STREPTOCOCCAL PROTEINASE BY SERA OF NORMAL AND IMMUNE ANIMALS AND OF PATIENTS INFECTED WITH GROUP A HEMOLYTIC STREPTOCOCCI.

Antiproteinase sera were prepared by immunizing horses with filtrates from a selected strain of group A streptococcus. This strain, which produced high titred proteinase but no erythrogenic toxin, was selected from forty-two strains of group A streptococci which produced varying amounts of proteinase. A few strains belonging to groups B, C, and G were also tested; they were all proteinase-negative.

SOME ASPECTS OF SECRETION : I. SECRETION OF WATER.

If we increase the osmotic pressure at one end of a Nitella cell by applying a solution of sucrose and if we subsequently submerge the entire cell in water we find that water enters at the end where the osmotic pressure is higher and comes out of the cell at the other end. If similar inequalities of osmotic pressure should arise as the result of metabolism we can understand how a secreting cell might take up water at one spot on its surface and expel it in another spot and thus bring about the secretion of water. The Nitella cell can expel water from a region of the cell which is in contact with water, air, or mineral oil.

ACTION OF PAPAIN AND FICIN ON TADPOLES AND ARBACIA EGGS.

Living tadpoles and Arbacia eggs are not digested by ficin or papain although the dead organisms are. Arbacia eggs develop in papain solutions but the cells become separated. Development is normal in ficin and trypsin solutions.

STUDIES ON THE FLEXNER GROUP OF DYSENTERY BACILLI : VI. THE DETOXIFICATION OF SHIGELLA PARADYSENTERIAE BY MEANS OF PERIODIC ACID.

A method for detoxifying Type Z and sp. Newcastle Sh. paradysenteriae (Flexner) has been described.

THE OCCURRENCE DURING ACUTE INFECTIONS OF A PROTEIN NOT NORMALLY PRESENT IN THE BLOOD : IV. CRYSTALLIZATION OF THE C-REACTIVE PROTEIN.

A procedure is described for the isolation and crystallization from human serous fluids of the C-reactive protein, a substance which appears in the blood especially in the early phase of certain acute infectious diseases. Immunological studies confirm earlier work in showing that the protein is highly antigenic and serologically specific, and demonstrate that crystallization of the protein effectively separates it from normal serum proteins.

THE NEOPLASTIC POTENTIALITIES OF MOUSE EMBRYO TISSUES : III. THE TUMORS ELICITED FROM GASTRIC EPITHELIUM.

Epithelial tumors have been readily obtained by the implantation of embryo stomach tissue together with olive oil containing methylcholanthrene (with or without Scharlach R) in adult mice of homologous strain. The implanted tissue from the squamous portion of the stomach rapidly encysted the oil, and benign and malignant papillomas and squamous cell carcinomas soon arose from the stratified squamous lining of the cysts. Bits of the glandular portion of the stomach also formed cysts, but the gland cells underwent metaplasia in response to the carcinogen, altering first to transitional epithelium and then to a stratified squamous layer.

NORMAL STRUCTURE AND DEGENERATIVE CHANGES OF THE CYTOPLASM OF LIVER CELLS AND OF TUMOR CELLS DERIVED FROM THEM.

Discrete bodies which may be designated cytochondria occupy the greater part of the cytoplasm of liver cells. A part, but not all, of these bodies have the characteristics of mitochondria. They consist of a rim which stains deeply and a central part which stains faintly or remains unstained.

ISOLATION OF A CRYSTALLINE PROTEIN COMPOUND OF TRYPSIN AND OF SOYBEAN TRYPSIN-INHIBITOR.

A crystalline protein compound has been isolated from a solution containing crystalline trypsin and crystalline soybean inhibitor. The protein consists of about equal weights of trypsin and of the inhibitor. Denaturation by heat or by alkali resolves the compound into its components.

CRYSTALLINE SOYBEAN TRYPSIN INHIBITOR : II. GENERAL PROPERTIES.

A study has been made of the general properties of crystalline soybean trypsin inhibitor. The soy inhibitor is a stable protein of the globulin type of a molecular weight of about 24,000. Its isoelectric point is at pH 4.

AN INACTIVE PRECURSOR OF STREPTOCOCCAL PROTEINASE.

1. Streptococcal proteinase is derived from an inactive precursor found in culture filtrates of proteinase-producing streptococci. 2.

SOME PROPERTIES OF PROTOPLASMIC GELS : II. CONTRACTION OF CHLOROPLASTS IN CURRENTS OF WATER ENTERING THE CELL AND EXPANSION IN OUTGOING CURRENTS.

The chloroplasts of Nitella may contract under natural conditions as well as under the influence of certain reagents. When a sufficient amount of water enters any part of the cell they contract in that region and they expand when the direction of the current is reversed. The current may be produced by placing water at one end of the cell and applying at the other end a solution which withdraws water from the cell.

THE NUCLEIC ACID AND CARBOHYDRATE OF INFLUENZA VIRUS.

Both ribonucleic and desoxyribonucleic acids have been obtained from purified particles of PR8 influenza virus. These particles were also found by extraction with formamide to contain carbohydrate in addition to that of the nucleic acids. Carbohydrate-rich fractions, essentially devoid of nucleic acid, were obtained not only from the particles representing PR8 virus but from those of Lee influenza virus as well.

THE EFFECT OF LIPIDS AND SERUM ALBUMIN ON BACTERIAL GROWTH.

Long chain fatty acids have been found to exhibit both inhibitory and stimulatory effects on the growth of tubercle bacilli and of a certain unidentified micrococcus culture. The toxicity of the fatty acids was much reduced or abolished by (a) esterification, even when the resulting product was a water-soluble ester, and (b) addition of crystalline serum albumin to the culture medium; other proteins tested were inactive in this respect. Marked growth stimulation of the microorganisms studied was obtained when certain long chain fatty acids were added to the culture medium in the form of their water-soluble esters, or in admixture with adequate amounts of serum albumin.

PROPERTIES OF PNEUMONIA VIRUS OF MICE (PVM) IN RELATION TO ITS STATE.

Additional evidence is presented that PVM is capable of combining firmly with lung tissue particles or erythrocytes from certain susceptible species. Release of the virus from such combination can be effected by treatment with alkali as well as by heating. Free virus expressed from infected lungs without grinding the tissues is infectious and causes hemagglutination when tested directly.

CENTRIFUGATION STUDIES ON PNEUMONIA VIRUS OF MICE (PVM) : THE RELATIVE SIZES OF FREE AND COMBINED VIRUS.

A technique has been devised for obtaining free or uncombined pneumonia virus of mice (PVM). Free PVM, liberated from infected mouse lungs by means of this technique, is infectious and causes hemagglutination directly. The results of quantitative studies carried out in the high speed angle centrifuge indicate that the free virus is relatively small, with dimensions of the order of 40 millimicrons.

REACTION OF ENZYMES AND PROTEINS WITH MUSTARD GAS (BIS(beta-CHLOROETHYL)SULFIDE).

1. The rate of reaction of mustard gas (H) with thirteen proteins has been determined. The extreme variation in reaction rates is about 100:1.

CRYSTALLIZATION OF PEPSIN FROM ALCOHOL.

1. Pepsin is soluble in 65 per cent alcohol and may be readily crystallized from 20 per cent alcohol. The crystals appear as needles or plates which may be transformed into the usual hexagonal bipyramids by recrystallization from water.