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The effects of LSD on neuronal activity in the LGN were studied in cats anaesthetised with urethane. LSD was given in doses of 25 μg, 100 μg, 200 μg and 300 μg per cat. Changes in neuronal activity were compared with those observed in a control population of cells recorded from animals that had received 0.5 ml of physiological saline or no treatment. The spontaneous firing rate, the responses to light stimuli delivered to the centre and to the surround regions of the receptive fields were all depressed by the drug. There was a dose response relationship which was almost identical (slope, b = -0.19 to -0.20) for each of these aspects of LGN neuronal activity. In a given cell changes in spontaneous activity were not correlated with changes in the responses to field centre or surround stimulation. Changes in response to field centre stimulation were not predictive of changes in response to field surround stimulation except in the LSD≧ 100 μg treatment groups. In these groups the variances of the change in spontaneous activity were greater than those in the controls. It is concluded that, in the doses used, LSD does not exert a uniformly depressant action on postsynaptic membranes: the effects observed are consistent with an action on the release of transmitter substance and/or its interaction with receptors. BOL 148, the non-psychoactive analogue of LSD did not completely reproduce the effects of any dose of LSD used in this study. The possible consequences of the action of LSD on LGN neurones for the processing of visual information is discussed.

The use of triton beams from tritiated titanium inserts in a sputter ion source has become a significant part of the McMaster Nuclear Physics programme. Tritium beams have been run on the McMaster University FN Tandem since 1978 on the basis of one scheduled running period per year accumulating a total of over 4000 hours of running time. Beams of up to one microamp are routinely put on target. Procedures for safe maintenance and operation of such a source have been developed, and techniques for handling up to 40 TBq (about 1000 Ci) of tritium have been approved by the Atomic Energy Control Board.

Measurements of the heating of metal targets in air by laser pulses with plasma ignition have shown substantial enhancement of thermal coupling compared to simple infrared absorption. This heat is in some cases spread over an area much larger than the laser spot. We present direct measurements of the spatial distribution of aluminum target heating with a high‐energy (11 kJ, 40 μs) CO2 laser pulse. This observed distribution is compared to that calculated for a model of thermal coupling via thermal emission from a vertically propagating disk‐shaped plasma. This model yields a better fit to the data than is obtained for a model of coupling via thermal conduction from a hydrodynamically expanding plasma due to Robin.

Above a distinct threshold laser flux of 70‐MW/cm2 peak (for a pulse consisting of a 150‐ns spike and a 1.8‐μs tail), the calorimetrically measured effective absorptance of unpolished 3003 alloy aluminum increases abruptly to roughly 14%. While too high to be ascribed to ordinary metal infrared absorptance at any reasonable temperature, this value is typical of total‐energy thermal coupling in air with air plasma ignition. We propose that this absorptance is in fact due to the ignition of a plasma in metal vapor produced by thermally isolated metal defects, rather than to a metal‐dielectric transition.

Occlusion of the pulmonary artery branch to the right upper lung, in a man of 47 years, was suspected from the finding of a translucent area in the X-ray of his chest. This diagnosis was confirmed by angiogram, done during cardiac catheterisation.

The use of propylene glycol carbonate as a replacement solvent for dimethyl sulfoxide in a Coherent model 599-21 c.w. dye laser has been investigated. Up to 40 milliwatts of single frequency output was achieved at 875 nm.

It is sometimes assumed that in order to establish that compensation should be paid to children who are born malformed as a result of injuries done negligently to the foetus it is necessary to regard the foetus as having rights, and it is frequently argued that to admit that the foetus has rights provides the basis for a strong, perhaps overriding, argument against abortion. If this is so, then there are two conflicting tendencies in what might be called liberal social attitudes concerning the foetus. On the one hand there is the view, characteristically held by defenders of abortion, that the foetus has no rights to stand in the way of abortion where this is thought to be desirable, and on the other hand there is the view, held by some who wish to establish that antenatal injury gives rise to valid claims for compensation, that the foetus has rights on the basis of which damages may be awarded against the negligent perpetrators of such injuries. It may therefore appear to the supporter of abortion that he must resist the tendency to admit claims based on antenatal injuries on the grounds that he cannot have it both ways; consequently he must abandon his position on abortion or modify his views on antenatal injury. Thus it has been alleged that American law appears schizoid because it protects the right to property and bodily integrity of someone who has no legal right even to exist, with the paradoxical result that it is legally permissible to kill but not to injure the foetus.1 How, it is asked, can the law permit abortion while at the same time it allows posthumous children to inherit, forces mothers to have blood transfusions in the interests of the health of the foetus, and rules that a child which dies almost immediately after birth may recover for prenatal injuries caused early in the pregnancy? Consistency requires, surely, either that the foetus has the right to health and happiness, in which case abortion is ruled out, or that it has not, in which case antenatal injury to the foetus does not give rise to claims by the foetus for damages against those who caused the injuries. In this paper we shall consider various solutions to this liberal paradox