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490 consists of murder and robbery, or of more respectable offences like income-tax evasion, use of electric current during prohibited hours, or driving too fast in built-up areas. What he did not mention at all was the contri- bution of society itself to crime. Crime is correctly defined as an infraction of law ; we are only just beginning to realise that both the law and the infraction may be symptoms of a collective character disorder for which we are collectively responsible. Our collective short- comings are partly responsible for the present tangle of restrictive regulations with their infinite number of new offences ; they have also, by binding upon the weaker brethren burdens they are unable to bear, made inevitable much of the crime which is now beginning to cause us discomfort and anxiety. The problem of crime, while it certainly calls for examination of the offender and his circumstances, calls even more loudly for an examination of the social order against which he offends. THE MULTIPLICATION OF COAGULATION FACTORS THE orthodox faith of blood coagulation, based on the four agents, thromboplastin, prothrombin, calcium, and fibrinogen, has been able to survive repeated and determined heretical attacks because it offers the simplest explanation of those facts with which the average physio- logist is familiar. It is now becoming clear, however, that only as a framework can it continue to exist. Despite the notorious difficulty of obtaining reproducible results in this field of research it is apparent to even the most conservative that modern findings require a considerable elaboration of the old theory, or a new theory altogether. So far the tendency is to try to fit new facts into the old framework, though to some it may seem that the resulting structure is becoming a little unstable. The additions are in the form of " new factors." Some of these are thought to oppose the action of the accepted clotting mechanism, as, for instance, the antithromboplastin described by Tocantins,’- which he considers to be present in excess in haemophilia, and a similar, possibly identical, inhibitor studied by Feissly.2 On the other side of the balance a number of agents have been added by the recognition of the complex nature of factors previously stated to be simple. Thromboplastin is thought to consist of an enzyme (kinase) and a co-factor of lipoidal nature related to cephalin or lecithin.3 -Kinase itself is probably derived from an inactive precursor in the plasma, . studied under the name of " plasmakinen " by Laki.4 Several workers have come -to the conclusion that prothrombin is a complex of at least two components,5 and even fibrinogen has not preserved its undivided identity. Now, distinct from these fission products of the old clotting factors, come the new "factors v and vi " described by Owren in our columns last week. The evidence that he puts forward must be accepted as being strongly in favour of the existence in normal plasma of an accessory to thromboplastin and calcium essential to their proper action on prothrombin. In his present communi- cation the evidence for " factor VI" is less convincing, but will no doubt be presented in full later. The existence of an additional factor of the type postu- lated by Owren had already been suggested by the work of Fantl and Nance s in which they found that, while highly purified preparations of prothrombin could be only slowly converted to thrombin by thromboplastin 1. Tocantins, L. M. Amer. J. Physiol. 1943, 139, 265. 2. Feissly, R. Helv. med. Acta, 1944, 11, 177. 3. Loathes, J. B., Mellanby, J. J. Physiol. 1939, 96, 38P ; Macfarlane, R. G., Trevan, J. W., Attwood, A. M. P. Ibid, 1941, 99, 7P. 4. Laki, K. Studies from the Institute of Medical Chemistry, University Szeged, 1943, vol. III, p.5. 5. Quick, A. J. Amer. J. Physiol. 1943, 140, 212 ; Nolf, P. Arch. int. Pharmacodyn. 1945, 70, 5; Feissly, R. Schweiz. med. Wschr. 1945, 75, 696. 6. Fantl, P., Nance, M. Nature, Lond. 1946, 158, 708. and calcium, the addition of prothrombin-free plasma resulted in a great acceleration of the reaction. Whether, as seems likely, these findings can be explained on the same basis as those of Owren only future work can determine. In any event a fresh impetus to research on blood coagulation has been given by Owren’s observa- tions, and, as always, a new discovery may have unexpectedly wide and exciting results. The case of factor V deficiency he describes is obviously an example of an extremely rare condition, but its intelligent investiga- tion has shown once again how important human material can be to the experimentalist, a fact often ignored in academic circles. It provides, too, still another example of how increasing knowledge appears to reveal an almost infinite complexity underlying even the simplest biological process. And yet, in this particular instance of blood coagulation, the intricacy seems almost too lavish. Do all these factors, whose number now runs into double figures, really exist in the blood for the express purpose of controlling the occasional conversion of fibrinogen to fibrin, or do they, under other names, take part in other and more continuous metabolic processes ’? Or is it, perhaps, that one’s dissection of the dynamic whole creates a series of static artefacts ’? DOCTOR DEMAND IN A HEALTH SERVICE WHEN everyone can get medical advice without paying directly for it, what increase may we expect in the demand for doctors’ aid ? Sound planning for a new health service requires some estimate of the amount of professional attention people will want ; and this problem has been studied in Canada, now also engaged on tentative plans for universal State-aided medical care. Although it would be unwise to apply generally to this country the experience of a particular town in Eastern Canada, yet the results of a morbidity survey made some time ago by Richter in two Nova Scotian communities are certainly relevant. This survey covered a year’s record of the services given by the local doctors in Glace Bay, a typical mining town, and Yarmouth, a non-industrial town in the same area. There were differences in the age-sex composition, and the economic and industrial background of the populations, but the most important difference was in the method of providing for medical care. In the mining town a contri- butory insurance scheme assures treatment by general practitioners, hospital care, operations, drugs, and dressings for each worker and his dependants. In the rather more amuent Yarmouth the fee-per-service system operates, the usual charges being$2 (lOs.) for a surgery consultation and$3 (15s.) for a visit. The contributory scheme had been in operation in Glace Bay for about 80 years, and the level of demand had become stabilised. Records were kept of the number of professional services rendered by the practitioners in each town to all members of the communities during the 12 months of the survey, and comparisons between the incidence-rates of treated illnesses were then made. " Clearly such comparisons were complicated by the occupational, economic, and demographic differences of the two populations, but some of the results which were relatively unaffected by these difficulties are significant. In both communities two-thirds of the services were given to the workers’ dependants, but an important difference was revealed : under the insurance scheme the larger families-with eight or more members- had twice as much medical care as families of the same size had under the fee-for-service regime. It appears then that, when assured provision is- absent, the larger 1. Richter, L. The Effect of Health Insurance on the Demand for Health Services. Canad. J. Econ. polit, Sci. May, 1944, p. 179.
