This Hospital of St. John is perhaps the most perfect we have in France. It is housed in good wooden huts, amply spaced out and admirably planned for convenience in working and administration; each wooden ward is light, airy, cheerful in colour and provided with every imaginable aid to cleanliness and good order. One of its special belongings is a cardiograph, or apparatus for recording on a chart, by the help of electricity, all the movements of the heart, so that in cases of irregular action of the heart the evenly serrated line produced on the paper by a normal heart action is varied with spasmodic upward leaps or downward collapses. Varied Conveyances. Between the front and the base a wounded man may travel, for some part of the way, in any one of a large variety of conveyances. The ordinary stretcher and the overhead trolley have been mentioned. The wheeled stretcher, balancing like a dog-cart between two large bicycle wheels, or between two smaller ones with pneumatic tyres, is extremely useful for saving jolts and labour. Its chief sphere of action is between the rear ends of communication trenches and the points, perhaps a mile or two farther on, beyond which it is not advisable for motor ambulances to go. But of course it can only be used to advantage where the ground to be traversed is not completely broken up by shell fire, mines or bombs. Narrow-Gauge Railways. An excellent way of transporting casualties—where it is available—is by the narrow-gauge Decauville railways which now carry stores and ammunition up from many of our full-gauge railheads to the front line, or near it. A photograph shows two ambulance trolleys accommodating four laden stretchers. A similar trolley is used at some casualty clearing stations to convey patients from the wards to the Red Cross train by which they are to be evacuated. Such contrivances are sometimes invented independently, in slightly different forms, by the staffs of different clearing stations or hospitals. Like the combatants, the medical officers are constantly devising new methods and new apparatus to meet the changing needs of active service. Motor Ambulances. The motor ambulance, to carry four stretcher patients, is the regular means of conveyance from a few miles behind the front line to the casualty clearing stations at the railheads. “Sitting wounded” travel either in motor ambulances, with the interior arranged to receive them, or in motor lorries—usually in the former. From the casualty clearing stations the wounded go to the base, as a rule, either by train or by canal. Water Transport.