No abstract

Forty-four collected cases of ulcerative tracheo-oesophageal fistula following tracheostomy and assisted ventilation are reviewed. The condition followed this form of treatment in 05% of cases and must be distinguished from fistulae caused by accident or surgery, and also from laryngotracheal paralysis or dysfunction. The symptomatology, diagnosis, and treatment are discussed in detail. Spontaneous cure of fistulae is rare, and operative closure should be the aim. In one patient in six, surgical closure is excluded by rapid death. When surgery is possible its timing requires critical judgement. Factors requiring assessment are the condition of the patient and of the tissues around the fistula, the necessity to continue assisted ventilation, and the ability to control nutrition, tracheal aspiration from the mouth or stomach, and pulmonary infection. The mortality of those who did not die too rapidly to receive treatment was 61 % without surgery and 45-5% with surgery.

THE following case was reported in detail up to 1953 by Lewis and Rogers (1953), and a summary only of their findings will be given here. since that time the patient has developed dysphagia, caused by a in the chest.to rest, he became short of breath on walking to school, and his lips became blue at times. In the region of the right common carotid artery there was an oval pulsating swelling, measuring I in. in its long axis, over which was a thrill and a bruit. On the left side axillary pulsations were absent. Pulsation in the right arm and over both CASE REPORTfemoral arteries was normal. The blood-pressure in the right arm was 95/64 mm. Hg. The cardiovascular system was otherwise normal, the electrocardiogram was normal, and radiography showed minimal enlargement of the heart and slight widening of the upper mediastinal shadow.ring surrounding the trachea and mso~~hagus were faint, while the brachial, radial, and ulnar pulses

The bone mineral content (BMC) of the lower end of the femur was measured by photon absorptiometry in 87 patients with chronic renal failure. The gamma-ray photon source was Am241. Serial measurements were obtained for up to two years. The mean BMC of the adult patients, comprising: 18 pre-dialysis (CRF), 41 chronic haemodialysis (CHD) and 19 renal transplant (RT) patients were all significantly lower than controls with the exception of the male CRF group. Two adults and one child on chronic haemodialysis showed a significant rate of bone loss (less than 2% per year). In one of these adults the addition of daily oral 1 alpha hydroxycholecalciferol was associated with no further reduction in BMC. Two children and one adult on chronic haemodialysis showed a significant rate of increase in BMC (less than 2% per year). This adult had had a tendency to loss of BMC on standard CHD treatment but after receiving parenteral 1,25 dihydroxycholecalciferol three times weekly showed a significant rate of loss of BMC on serial measurement. Two adults and one child with CRF had a significant rate of increase in BMC on standard treatment.

PHYSIOLOGY OF VISION: RECENT ADVANCES MEDICAL URNA639properties of vision which up to now have been difficult to explain. One of these is the retinal direction effect of Stiles and Crawford. This aspect of the cluster hypothesis is to be dealt with in detail elsewhere. Using as test objects extremely small disks, it has been possible to identify the position of some of the clusters near the centre of a human fovea. This matter is also to be considered in detail elsewhere.Section V: The Antichromatic ResponsePhysiologists have long been puzzled by one property of the lens-system of the eye-namely, the absence of colour from the images of colourless obiects which itrproduces on the retina. A lens employed for photographic, microscopic, or similar purposes has to be achromatized by the use of convex crownglass lenses in conjunction with concave flint-glass ones. Such combinations of lenses bring light of different colours to the same focus. Such is not the case if a single lens, either of flint glass or of crown glass, is used by itself. Thus a convex lens brings the violet rays to a focus first; then follow in order the blue, the blue-green, the green, the yellow, the orange, and, lastly, furthest from the lens, the red. It has been shown by experiment that this is the order of the colours in the case of the eye. It has also been shown that it is the yellow-green rays that are sharply focused on the retina under normal circumstances. The consequence is that the orange and red ravs, which have not yet come to a focus, form blurs on the retina; so also do the violet, blue, blue-green, and green rays, because, having come to a focus, they diverge again before they reach the retina. The image on the retina of a small bright white light on a black background will thus take the form of a yellow spot of high intensity surrounded by a blue halo or fringe which consists of the unfocused colours. So far theory and observatiorj have been in close agreement; but now thev differ to a startling extent. For when the observer looks at a small bright light he does not see either the yellow spot or the blue fringe. What he sees is the white light unaccompanied by any colours. Similarly in the case of other objects, both black and white: when these are looked at, coloured fringes-yellow or blue-should be visible owing to the chromatic aberration of the eye. But observation shows that in fact all such effects are conspicuously absent. In the past numerous hypotheses have been advanced to explain the absence of chromatic fringes from vision, but none of these has been able to stand critical examination. The the blue is replaced by dark grey or black, while the yellow is replaced by white. Further details will be given elsewhere, together with the reasons for concluding that somewhere on the pathways between the retina and the brain there are situated nerve centres, one of which deals with blue while the other deals with yellow; and that these two in conjunction have the function of eliminating from vision the spurious colours produc...