CAPACITY OF PLEUROPNEUMONIA-LIKE MICROORGANISMS TO GROW ON CHORIOALLANTOIC MEMBRANES.

1. Among eight strains or variants, included in four different immunological types of pleuropneumonia-like microorganisms, all grew on chorioallantoic membranes; those belonging to Klieneberger's Type L(5) (Sabin Type A) grew very poorly; and those included in three other types grew with varying degrees of vigor. 2.

THE MAGNETIC BEHAVIOR OF CATALASE.

The magnetic moment of catalase is 4.6 +/- 0.3, nearly the same as that of ferric hemoglobin hydroxide.

INACTIVATION OF PEPSIN BY IODINE : II. ISOLATION OF CRYSTALLINEl-MONO-IODOTYROSINE FROM PARTIALLY IODINATED PEPSIN.

1. Pepsin solutions were iodinated at pH 5.0-6.

COMPARATIVE VIRULENCE OF ST. LOUIS ENCEPHALITIS VIRUS CULTURED WITH BRAIN TISSUE FROM INNATELY SUSCEPTIBLE AND INNATELY RESISTANT MICE.

We find that St. Louis encephalitis virus cultured in 10 per cent serum-Tyrode solution plus brain tissue from 1-day-old innately susceptible mice attains a higher titre than when cultured in a similar solution plus brain tissue from 1-day-old closely related, yet innately resistant mice. This difference in titre persists regardless of whether the serum comes from innately susceptible or resistant mice.

INFLUENCE OF EXTRANEOUS PROTEIN AND VIRUS CONCENTRATION ON THE INACTIVATION OF THE RABBIT PAPILLOMA VIRUS BY X-RAYS.

The pronounced resistance to the x-rays manifested by the papilloma virus in ordinary suspensions is due to the protecting influence of extraneous matter and also in considerable degree to the amount of virus present in the preparation. Two to 4 million r were required to inactivate the virus contained in the crude papilloma extracts prepared for the present work, whereas 100,000 r or less was enough to inactivate comparable concentrations of virus after extraneous matter had been excluded by repeated differential centrifugation. The addition of normal rabbit serum or crystalline egg albumin to purified suspensions of virus was found to increase greatly the amount of irradiation required to inactivate the virus.

STUDIES ON CONDITIONS AFFECTING THE SURVIVAL IN VITRO OF A MALARIAL PARASITE (PLASMODIUM LOPHURAE).

The survival of Plasmodium lophurae in vitro, at temperatures of 39.5-42 degrees C., is favored by a balanced salt solution having a high potassium content, by aeration but not by a very high oxygen tension, by an optimal density of parasites per cubic millimeter, by frequent renewal of the suspending medium, by concentrated red cell extract, by optimal concentrations of plasma or serum, of chick embryo extract, of glucose or glycogen, and of glutathione, and probably by yeast extract and a very low concentration of liver extract.

CULTIVATION OF THE HOG CHOLERA VIRUS.

The work of Hecke on the cultivation, of hog cholera virus was confirmed with ease. Virus was grown in the presence of fresh minced swine testicle in flasks containing Tyrode solution, on the chorioallantoic membrane of embryonated eggs, and on the surface of swine serum agar. In flasks it was grown for 14 transfers; while on eggs it was grown for 13 transfers, followed by an equal number of transfers on agar, making 26 transfers in all.

THE COMPLEMENT FIXATION TEST IN THE DIAGNOSIS OF VIRUS INFECTIONS OF THE CENTRAL NERVOUS SYSTEM.

A specific complement fixation test can be obtained in various central nervous system virus infections by using as antigens emulsions of infected brain tissue, freezing and thawing the brain emulsion, and then centrifuging it in an angle head centrifuge at 3500 R.P.M.

EXPERIMENTAL NEPHRITIS IN RATS INDUCED BY INJECTION OF ANTIKIDNEY SERUM : V. CHRONIC NEPHRITIS OF INSIDIOUS DEVELOPMENT FOLLOWING APPARENT RECOVERY FROM ACUTE NEPHROTOXIC NEPHRITIS.

1. Three different inbred lines of rats were found to vary in their response to antikidney serum: rats of the Whelan strain were most susceptible to nephrotoxin and most prone to develop chronic glomerulonephritis immediately following the acute injury induced by this agent; animals of the Evans strain were almost as vulnerable to the acute effects of nephrotoxin; Wistar rats were the least affected. 2.

THE DETECTION OF A "MASKED" VIRUS (THE SHOPE PAPILLOMA VIRUS) BY MEANS OF IMMUNIZATION : RESULTS OF IMMUNIZATION WITH MIXTURES CONTAINING VIRUS AND ANTIBODY.

A study has been made of the immunization procedure described by Shope, with particular reference to the detection of "masked" papilloma virus by means of it. Papilloma extracts were frequently encountered which, though non-pathogenic, elicited the specific antiviral antibody and induced resistance to the virus upon injection intraperitoneally into normal rabbits. The results of the immunization experiments were often complicated, however, by the effects of extravasated antibody, which had accumulated in various amounts in many of the papillomas and was consequently present in extracts of them together with "masked" virus.

STUDIES ON AN AGGLUTINOGEN (Rh) IN HUMAN BLOOD REACTING WITH ANTI-RHESUS SERA AND WITH HUMAN ISOANTIBODIES.

Studies are reported on an individual agglutinogen (Rh) in human blood which has been found to be of clinical importance because occasionally it gives rise to the formation of immune isoantibodies in man, a peculiarity which leads to untoward transfusion reactions. A method for the determination of the presence or absence of the new blood factor is described, which can be used for typing patients and prospective blood donors. Examination of families showed that the agglutinogen is inherited as a simple Mendelian dominant.

THE EFFECT OF CALCIUM AND OTHER IONS ON THE AUTOCATALYTIC FORMATION OF TRYPSIN FROM TRYPSINOGEN.

Crystalline trypsinogen is completely transformed into trypsin by means of trypsin in the presence of calcium salts. The process follows the course of a pure autocatalytic unimolecular reaction. In the absence of calcium salts, the autocatalytic formation of trypsin from trypsinogen is complicated by the transformation of part of the trypsinogen into an inert protein which cannot be changed into trypsin by any known means.

THE BEHAVIOR OF POX VIRUSES IN THE RESPIRATORY TRACT : IV. THE NASAL INSTILLATION OF FOWL POX VIRUS IN CHICKENS AND IN MICE.

Fowl pox virus from active skin lesions was established in the upper respiratory tract of normal chickens by nasal instillation and maintained for 12 successive passages. The nasal infection was not communicable by direct contact but did afford protection, for at least 6 weeks, against subsequent development of the virus in the skin. Multiplication of the virus in the nasal passages was only irregularly attended by specific mucosal changes and was not accompanied by the vigorous counter-reaction engendered by the causal agents of roup.

CONSTITUENTS OF ELEMENTARY BODIES OF VACCINIA : V. A FLAVIN ASSOCIATED WITH THE PURIFIED VIRUS.

Suspensions of purified elementary bodies of vaccinia exhibit fluorescence in the presence of ultraviolet light. This fluorescent constituent can be separated by chromatographic methods provided the virus is first denatured by acid and heat. By means of the specific protein of d-amino acid oxidase it has been possible to identify the flavin constituent as flavin-adenine-dinucleotide and show that it can participate in the oxidative deamination of d-alanine.

INFLUENCE OF AGE ON SUSCEPTIBILITY AND ON IMMUNE RESPONSE OF MICE TO EASTERN EQUINE ENCEPHALOMYELITIS VIRUS.

The experiments described in this paper were carried out with the Rockefeller Institute strain of albino mice and with the Eastern strain of the virus of equine encephalomyelitis. 1. The observation was confirmed that with increasing age of mice there occurred a decrease in susceptibility to intraperitoneal injection of active virus; also, the length of incubation period of those which succumbed increased with age.

SULFHYDRYL GROUPS IN FILMS OF EGG ALBUMIN.

1. The same number of SH groups reduces ferricyanide in surface films of egg albumin as in albumin denatured by urea, guanidine hydrochloride, Duponol, or heat, provided the ferricyanide reacts with films while they still are at the surface and with the denatured proteins while the denaturing agent (urea, heat, etc.) is present.

SULFHYDRYL GROUPS OF EGG ALBUMIN IN DIFFERENT DENATURING AGENTS.

1. The reaction between ferricyanide and egg albumin in solutions of urea, guanidine hydrochloride, and Duponol has been investigated. 2.

EFFECTS OF NITROBENZENE AND BENZENE ON VALONIA.

The effects of nitrobenzene and of benzene resemble those of guaiacol and of hexylresorcinol. The P.D.

SOME EFFECTS OF IODINE AND OTHER REAGENTS ON THE STRUCTURE AND ACTIVITY OF TOBACCO MOSAIC VIRUS.

1. Denatured tobacco mosaic virus has a number of SH groups corresponding to its total sulfur content of 0.2 per cent.