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A method for the simultaneous determination of plasma prothrombin and antithrombin III has been developed. It involves activation of a dilute plasma solution with Taipan snake venom and measurement of the heparin-mediated loss of thrombin activity after short incubation. The antithrombin III content is quantitated on the basis of results with known mixtures of normal and antithrombin III-deficient plasmas.

Head-body temperature differences of up to 5.7° and 6.1° C were observed during solar and radiant heating, respectively. Head temperature was more precisely regulated than body temperature and within preferred limits head temperature was significantly lower than body temperature. Higher temperatures were tolerated by the body than the head. Preferred temperatures for both the head and body are higher in the taipan than in other ophidians which have been reported upon, and approximate those temperatures reported for the voluntary maxima in other snakes.

Thrombin formation in mixtures of purified prothrombin, Taipan snake venom, phospholipid, and CaCl2 was studied as a function of varying concentrations of individual components of the reaction mixture. Under optimal conditions prothrombin yielded stable thrombin activity, rapidly and quantitatively, providing the basis for a convenient assay of purified prothrombin.

KUNUKBAN is the most common Aboriginal name for the black-headed python (Aspidites m. melanocephalus) in the Ord-Victoria region of north-west Australia. In north Australia generally, ancestral snake heroes are common (Fig. 1). Well-known examples are Taipan (McConnel, 1957), Unjaut (Mountford, 1956), Galani or Ungud (Elkin, 1930), WoUunqua (Spencer and Gillen, 1912) and N'gama (Bjerra, 1956). Bolan is a lesser known snake hero in the Katherine-Roper River region (Arndt, unpublished). This paper reports Kunukban as an ancestral snake hero in the Ord-Victoria region. Since very little mythology has previously been reported for this region, a brief historical account of the region is given and the biography of the informant is reported in some detail. In order to appreciate the nature of the respect due to Kunukban, it is necessary also to briefly describe the nature of the old " wildtime religion/' which has practically died out but has not previously been reported. An attempt is made to explain why a limbless animal such as a snake is so commonly credited with the formation of landscapes and finally some thoughts on the future of Aboriginal religion are presented.

Complete activation of prothrombin with taipan snake ( Oxyuranus scutellatus scutellatus ) venom yields thrombin and two fragments, fragment-1 and fragment-2, which by the criteria of ion-exchange chromatography and SDS gel electrophoresis are indistinguishable from the products of Xa-catalyzed prothrombin activation. Activation in the presence of diisopropylfluorophosphate with either taipan venom or Xa results in the formation of thrombin-sensitive fragment 1·2, a single polypeptide composed of fragments-1 and 2. Whereas the rate of venom-catalyzed activation is enhanced 20–30 times by phospholipid vesicles, Factor V is without effect in either the presence or absence of phospholipid. The venom activity is not inhibited by diisopropylfluorophosphate, phenylmethylsulfonylfluoride, soybean trypsin inhibitor, p-hydroxymercuribenzoate or iodoacetate. The venom does not hydrolyze N2-toluene-p-sulfonyl-L-arginine methyl ester, N2-benzoyl-L-arginine ethyl ester or N-acetyl-L-tyrosine ethyl ester. The rate of venom-catalyzed prothrombin activation is not affected by plasma factor Xa inhibitor plus heparin.

Established procedures for the isolation of human prothrombin (1) and thrombin (2) have been modified so that large quantities of human thrombin could be isolated in a rapid, yet facile, manner. Thrombins derived from the activation of human prothrombin with thromboplastin or venom from the Australian Taipan (Oxyuranus Scutellatus Scutellatus) have been isolated and characterized with respect to their molecular weights and isoelectric points. Multiple active human thrombin components were found. Molecular weights of proteins found in these preparations conformed to the molecular weights reported for bovine thrombins. Activity studies with the synthetic substrate Benzoyl-Phe-Val-Arg-p-nitro-anilide and inhibitors fibrinopeptides A and B, have been performed. The majority of coagulant and esterase activity of the human thrombin preparations was associated with a protein component with an isoelectric point of 7,1. Coagulant, but no esterase activity, was found at isoelectric point 6, 7. Additional minor peaks of both activities had isoelectric points of 5,6 and 6,2, which are the sole isoelectric points reported previously for bovine thrombin. Results of the characterization studies show that thromboplastin and taipan venom activation produce very similar thrombins.

Summary. A simple one-stage assay for the measurement of prothrombin employing the Taipan snake venom is described. The venom converts prothrombin to thrombin in the absence of all other known clotting factors.

Seventeen elapid antivenins and one sea snake antivenin were tested for neutralizing activity against a panel of fifteen elapid venom samples (eight Naja, three Bungarus, one each of Ophiophagus, Hemachatus, Walterinnesia and Micrurus) and one sea snake (Enhydrina) sample. Assays were made by injecting mice subcutaneously with 2–10 ld 50 of venom and injecting antivenin intravenously immediately thereafter. Antivenins against venoms of certain Australian snakes (tiger snake, death adder, taipan) protected animals against at least fifteen of the venoms used. Tiger Snake Antivenene neutralized ten of the venoms at a dose of 10 ld 50. Sea Snake Antivenene showed at least some protective effect against fourteen of the fifteen elapid venoms used, but most elapid antivenins failed to neutralize sea snake venom. Cobra antivenins proved largely genus specific and showed considerable variation in neutralizing capacity. Venoms of Naja n. atra and N. nigricollis were less well neutralized than other cobra venoms. Krait antivenins were relatively ineffective even in homologous systems. Coral snake (Micrurus fulvius) venom proved very difficult to neutralize. Certain implications of these findings are discussed and suggestions made for utilizing the paraspecific effect of elapid antivenins in clinical situations.