(1) D. albipictus, known as the winter or moose tick, is a common parasite of moose, elk and deer in the forests of northern Saskatchewan. As in the outbreak described in this paper, it may attack and cause serious losses among the cattle and horses of settlers which are permitted to graze in the haunts frequented by its native hosts. Deaths among the moose are frequently attributed to the ravages of the tick.(2) The eggs of D. albipictus are deposited in the ground by the engorged females, which continue to drop from the hosts throughout the winter until the beginning of May. The larvae emerge from the eggs during the late summer and probably remain dormant until such time as the period of drought passes and cooler weather arrives. Attachment to the host is achieved by the larvae in the autumn, and both the larval and nymphal moults are undertaken on one and the same host. During the summer months the hosts are free from its attacks.(3) Infestation of cattle and horses may be prevented by their maintenance in fenced, tick-free pastures or in barns from the end of September until the beginning of May. Animals that have become infested may be treated with an arsenical dip. Dipping, however, cannot be safely accomplished after September in northern Saskatchewan because of the risk of severe chills that may be contracted by treated animals consequent on the low prevailing temperatures of the autumn months.Tick-infested fields may be cleaned by being ploughed in the spring after all the ticks have dropped. The engorged females are buried, and even though the eggs may hatch, the larvae will find difficulty in reaching the surface in the autumn to attach themselves to a host.

IN 1923, Bramwell, Hill and McSwiney(l) published the results of investigations on the transmission of the pulse wave by recording simultaneously the carotid and radial pulses. A series of seventy-four observations on normal subjects showed a definite relationship between age and velocity. About the same period, Bazett and Dreyer(2) demonstrated that the pulse wave velocity was lower in the brachial than the radial artery, which suggests a greater extensibility of the central artery. These observers were, however, primarily interested in the relationship of pulse wave velocity to blood-pressure, and endeavoured to correlate their results with the measurements made by B ram well and Hill(3) on the pulse wave velocity in the isolated human artery with varying internal pressures. No systematic survey was made by B a z e t t and D reyer of the velocity of the pulse wave or extensibility of the carotid and peripheral arteries in normal individuals: Hiirthle(4), in 1923, showed that the femoral artery is normally less extensible than the carotid artery. This observer investigated the relation between internal pressure and volumetric expansion in living animals by applying a plethysmograph. Using a physical formula, which took into account the diameter and thickness of the vessel wall, Hiirthle showed that there was a progressive decrease in the extensibility of the vessels in the arterial path. The present investigation was undertaken to establish the relationship of the pulse wave velocity and extensibility of the brachial and radial arteries with age and, if possible, with the bloodpressure.METHOD. The velocity of the pulse wave was recorded by use of the hot wire sphygmograph as previously described(l). Records were taken from the carotid, brachial and radial arteries of the right arm, with the subject sitting at rest in a chair. A small glass funnel was used to record the

On June 10th, 1923, a practising veterinary surgeon brought into the Pathological Laboratory at the University scrapings that he had obtained from a herd of cattle which were suspected of being mangy. The sample was examined for mites without success. The veterinary surgeon said that the lesions were not typical of mange, but if it was not mange, it was some form of dermatitis which was unknown to him.

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