2
491 venous stasis inside the eye is produced. There seems much to support this argument for it is clear that peripheral retinal haemorrhages-which sometimes occur -could not come from direct extension from the nerve sheath. Ballantyne,2 in five fatal cases of subarachnoid haemorrhage, found that there were often scattered haemorrhages throughout the orbit, in the fat and around the ciliary ganglion. They seemed to have no connexion with the subarachnoid hsemorrhage and Ballantyne submits that the old story of direct extension from the cranium will not do. He concludes that the changes he found in the orbit can only be accounted for by some mechanism which produces venous stasis in the whole orbit, and suggests that we have such a mechanism in the sudden and forcible increase in intracranial pressure produced by the haemorrhage, which in turn causes. pressure on the venous sinuses inside the cranium. One would have thought, however, that the extensive alternative venous drainage of the orbit by -way of the facial and deep facial veins would have prevented venous stasis in the orbit. Dup-uy-Dutemps3 3 quotes some experiments by Sicard in which grains of chinese ink injected into the subarachnoid space of living animals found their way through the dural sheath and into the cellular tissues. This seems to offer an alternative explanation to the findings in the orbit in these patients. GLYCOLS IN AIR-DISINFECTION THE bactericidal action of both mists and vapours has been investigated in relation to the control of cross- infection in respiratory diseases, and it is generally agreed that vapours are effective provided they are sufficiently concentrated. But since Bechhold 4 asserted that weight for weight phenolic bactericides were much more efficacious as mists than as vapours attention has been mainly turned to the production of stable and durable mists. Robertson and his colleagues 5 of Chicago have found that propylene glycol, much used by previous workers as a solvent for germicides, is itself germicidal, and is more effective as a vapour than when an equal quantity is dispersed in droplets l,u to 2jM in diameter as an aerosol. At a temperature of 20° C., they say, 1 g. per 1’4 cubic metres of air saturates the atmosphere, though less than half this amount, evapor- ated from Petri dishes overnight, killed the various organisms tested almost at once. They demonstrated a very high lethal effect of the glycol when it was dispersed as an aerosol in a concentration of 1 g. per 2 cubic metres of air, or when dispersed as a vapour in about a quarter of that concentration. Actually vapours are presumably concerned in both cases, for small particles of most of the glycols evaporate completely in a few seconds or even a fraction of a second. Some of the other glycols acted as bactericides in the same way. Propylene glycol, however, has the advantage of being much better tolerated by animals. Cases of glycol poisoning in man, even from inhalation of the vapours, have been reported,, but not, apparently, from propylene glycol. On the other hand, mice are apparently unaffected by living for weeks in an atmosphere supersaturated with ethylene glycol, although there is a limit, especially in females, to the amount they can take by mouth. Stokes and Henle 6 of Philadelphia have found ultraviolet irradiation and vaporisation of propylene glycol highly and about equally effective in preventing air-borne infection of mice with the virus of influenza A. The ultraviolet light was projected as a " curtain " in front of each cubicle and also in the upper part of the ward above the cubicles. The glycol was vaporised from a hot plate placed in front of an electric fan near one of the 2. Ballantyne, J. Glasg. med. J. 1942, 20, 1. 3. These de Paris, 1900. 4. Bechhold, H. 1935. Improvements in rendering micro-organisms innocuous. British patent No. 472,623. 5. Robertson, O. H., Bigg, E., Puck, T. T. and Miller B. F. J. exp. Med. 1942, 75, 593. 6. Stokes. J. and Henle, W. J. Amer. med. Ass. 1942, 120, 16. ward windows so as to give a concentration of 1 in 2-4 million. They also quote an unpublished controlled experiment by T. N. Harris in which a concentration of one part of propylene glycol vapour in 30-40 million parts of air was strikingly successful in protecting children in a convalescent home from respiratory infection. I METABOLISM OF PLASMA PROTEINS THOUGH easily accessible for study or assay, the plasma proteins have always been rather neglected by physio- logists. Starling early established that one of their functions was the exertion of colloidal osmotic pressure in, the circulating medium. This function is now well understood and the part it plays in the formation of lymph and of various types of cedema has been thoroughly explored. For many years Whipple 1 and his ’ colleagues have been studying in dogs the formation and the wider functions of the circulating proteins. One aspect of this work has been the intermittent removal of large amounts of plasma proteins to discover what type of diet will cause the most complete and rapid resynthesis. This approach has led to the conclusion that some dietary proteins are much more efficacious than others and that proteins which favour haemoglobin formation are not necessarily those which favour plasma- protein production; as might be expected, the proteins of serum itself are the most effective that can be taken by mouth. These views have not gone unchallenged however ; Melnick, Cowgill and Burack 2 found that serum proteins, casein and lactalbumin each give an equally good synthesis of plasma proteins. Further experiments in Whipple’s laboratory have shown that dogs which have been depleted’of plasma proteins for some time are abnormally susceptible to infections of many kinds and to poisoning with chloroform and organic arsenicals. The susceptibility can be removed in a day or two by a high protein diet, or immediately if considerable amounts of plasma protein are given intra- venously. The amino-acid methionine has the same effect. These observations may have considerable therapeutic significance. Some of the experimental results of these workers seem a little revolutionary to the ’ conventional physiologists. Thus they have shown that dogs may be maintained in nitrogen equilibrium for weeks solely by the intravenous injection of plasma protein. This suggests either that these proteins must be broken down in the liver and their amino-acids redis- tributed to other tissues according to their needs, or that the plasma proteins themselves must enter the cells of the body, there to be transformed into the proteins characteristic of the cell. Whipple favours the second hypothesis. It would be helpful to see this work con- firmed on another species before the results are accepted as applying to man. SPEED AND DELAYED FRACTURE UNION THE orthopsed has lately been heaping abuse on his own methods of treating the fractured tibia. Excessive traction, the pin, the non-padded cast, long immobilisa- tion have all been blamed, and it has been urged that it would be better to make certain by earlier and more frequent operation. J. P. Campbell at the Nottingham meeting of the Orthopaedic Assocation says : Not at all, lift up your hearts, you are at least as good as your forefathers at the treatment of these fractures. The " modern " delayed union of the tibia, he maintains, is due to the increased severity of the injury ; in the simple fracture union takes no longer than of old. In an analysis of 54 tibial fractures at the junction of middle and lower thirds, he divides the cases into slight-those arising in football, boxing or jumping; and severe- those that followed motor-cycle, gunshot wounds or 1. Whipple, G. H. Amer. J. med. Sci. 1942, 203, 477. 2. Melnick, D., Cowgill, G. R. and Burack, E. J. exp. Med. 1936, 64, 897.
