STUDIES ON BLOOD COAGULATION : II. THE FORMATION OF FIBRIN FROM THROMBIN AND FIBRINOGEN.

Although calcium is essential for the formation of thrombin, it can be recovered quantitatively from formed horse thrombin without affecting its coagulating activity. Citrate also has no significant effect. As stated in the text, this does not exclude the possibility that thrombin is actually a calcium compound present in minute concentration; but confirming the results of Hammarsten, it does show that fibrin cannot be a calcium-protein compound unless one assumes molecular weights for fibrinogen greater than 1,000,000.

STUDIES ON BLOOD COAGULATION : I. THE ROLE OF PROTHROMBIN AND OF PLATELETS IN THE FORMATION OF THROMBIN.

1. A method is described for the preparation and titration of prothrombin and thrombin. 2.

SALT AND WATER LOSSES IN DIURETIN DIURESIS AND THEIR RELATION TO SERUM NON-PROTEIN NITROGEN AND ELECTROLYTE CONCENTRATIONS.

The losses of sodium, potassium, chloride, nitrogen, and water following the administration of diuretin to rabbits over 5 to 9 day periods together with the changes in serum concentrations of sodium, chloride, N. P. N.

THE ACCUMULATION OF IRON IN TUBERCULOUS AREAS : IV. THE EFFECT OF FERRIC CHLORIDE ON THE COURSE OF TUBERCULOSIS IN REINFECTED RABBITS.

Repeated intravenous injections of dilute ferric chloride solution in tuberculous rabbits markedly retard the development of the disease as evidenced both by a prolongation in the survival time and by comparison of lesions in control and experimental animals. Partial immunity induced by first infection combined with ferric chloride administration enhances in reinfected animals even more strikingly the favorable effects of the iron salt. Some of the experimental animals were still alive and apparently well about 6 months after the death of the last of the controls which succumbed about 4 months after reinfection with virulent tubercle bacilli.

THE SURVIVAL OF VARIETIES OF TYPHUS VIRUS IN MOUSE PASSAGE, WITH PARTICULAR REFERENCE TO THE VIRUS OF BRILL'S DISEASE.

The experiments above described have confirmed the observations of Laigret and Jadin that the European human typhus virus cannot be maintained for more than two generations in mice by brain-peritoneum passage; whereas the murine Mexican variety can be carried on by this method in mice through at least eleven passage generations. The fact that within eleven passages there is no attenuation of the murine virus renders it likely that this agent can continue in mice, in an inapparent form, without material modification. Brill's disease virus from three different isolations has behaved like the European type, a fact which strengthens the opinion previously expressed from this laboratory that Brill's disease represents an imported European strain of the classical European infection.

AN IMMUNOLOGICAL STUDY OF THE A SUBSTANCE OR ACETYL POLYSACCHARIDE OF PNEUMOCOCCUS TYPE I.

1. The A carbohydrate isolated from Type I pneumococcus by Pappenheimer and Enders, on the basis of elementary analysis, the presence of the acetyl group and its immunological properties, appears to be identical with the acetyl polysaccharide described by Avery and Goebel. 2.

THE ANTIGENIC RELATIONSHIP BETWEEN PROTEUS X-19 AND TYPHUS RICKETTSIA : II. A STUDY OF THE COMMON ANTIGENIC FACTOR.

A soluble specific substance was isolated from Mexican typhus Rickettsia which gave, with Proteus X-19 antiserum and typhus human serum, the same precipitation reactions as the polysaccharides extracted from B. proteus OX-19. The soluble specific substance extracted from Rickettsia and Proteus OX-19 is likely to be of a polysaccharide nature owing to the strong Molisch reactions obtained with such extracts, the heat stability and the negative protein reactions (biuret).

EPIDEMIC TREMOR, AN ENCEPHALOMYELITIS AFFECTING YOUNG CHICKENS.

A new disease having a characteristic and well defined symptom complex is described as occurring in young chickens in four New England states. Tremor, principally of the head and neck, and progressive ataxia are the characteristic symptoms, either or both of which may be present in a single bird. Age at onset in field epidemics ranges from 3 days to 6 weeks, with a majority of cases reported at 3 weeks.

STUDIES ON TYPHUS FEVER : XII. THE PASSIVE IMMUNIZATION OF GUINEA PIGS, INFECTED WITH EUROPEAN VIRUS, WITH SERUM OF A HORSE TREATED WITH KILLED RICKETTSIA OF THE MEXICAN TYPE.

Under uniform diet conditions the normal bile fistula dog will eliminate pretty constant amounts of cholesterol-about 0.5 to 1.0 mg.

THE FILTERING CAPACITY OF LYMPH NODES.

In anesthetized dogs the popliteal lymph node alone, and the popliteal and iliac lymph nodes in series, have been perfused with solutions containing dog erythrocytes and streptococci. The perfusions have been carried out under conditions of lymph flow and pressure within the limits of those occurring in the actively moving dog, or after a severe degree of inflammatory swelling has developed. Figures for filtration are given, with protocols of typical experiments.

THE TRANSPORT OF GAS BY THE BLOOD OF THE TURTLE.

The chief characteristics of the blood of the turtle Pseudemys concinna, considered as a system for the transport of oxygen and carbon dioxide, are its low corpuscular content (10 to 22 per cent by volume) and its high concentration of base bound as bicarbonate. These characteristics account fully for the shape and position of the carbon dioxide dissociation curve, the effect of oxygenation and reduction of the hemoglobin upon the carbon dioxide-combining power of the blood, and the distribution of carbon dioxide between the corpuscles and plasma. The oxygen-combining capacity of the turtle corpuscles does not differ from that of an equal volume of human erythrocytes.

THE FACTORS CONCERNED IN THE APPEARANCE OF NUCLEATED RED BLOOD CORPUSCLES IN THE PERIPHERAL BLOOD : II. INFLUENCE OF PROCEDURES DESIGNED TO INCREASE THE RATE OF BLOOD FLOW THROUGH THE BLOOD-FORMING ORGANS-HEMORRHAGE AND INFUSION.

1. Hemorrhage with immediate saline infusion causes the appearance in the peripheral blood of a slightly increased number of normoblasts provided normoblasts are already present in the blood stream. Marrow hyperplasia does not intensify this reaction and the cells found probably do not leave the marrow pulp but are in the blood stream at the time of the experiment.

THE FACTORS CONCERNED IN THE APPEARANCE OF NUCLEATED RED BLOOD CORPUSCLES IN THE PERIPHERAL BLOOD : I. INFLUENCE OF PROCEDURES DESIGNED TO INCREASE THE RATE OF BLOOD FLOW THROUGH THE BLOOD-FORMING ORGANS-EXERCISE AND NERVE SECTION.

1. Increase in circulatory rate caused by hard exercise has no power to dislocate nucleated red cells from the bone marrow either in normal, in anemic, in hyperplastic, or in anemic and hyperplastic animals. 2.