patient may slowly drift into a somnolent state or may not un- commonly combine somnolence by day with insomnia or restlessness by night. Rarely an attack commences suddenly with the wildest delirium or mania.
(II) Focal Nervous Symptoms. The positive symptoms include the following :
(1) Convulsions, which are occasionally generalized, resembling the epileptiform fit.
(2) Involuntary movements. These may develop during the attack or several months later in the course of convalescence. Nu- merous forms occur. The " myoclonic " type is characterized by short, rapid, rhythmic contractions of muscles, especially affecting the abdominal muscles and also the diaphragm, but the entire musculature or any group of muscles, or even a part of a single muscle may be affected. The contractions are 30 or 40 to the minute. Epidemic hiccough is possibly a variety of this type. Tremors, choreiform, athetoid and other movements of muscles may develop after the attack, some causing coarse spontaneous movements of large amplitude.
(3) Rigidity. This group includes the " Parkinsonian mask " and catalepsy, the latter being a condition of rigidity in which the limbs are retained for long periods in the position in which they are placed by an observer. The Parkinsonian mask, an expressionless facies, is common, and combined with rigidity produces the ap- pearance of acute paralysis agitans, or Parkinson's disease.
(4) Muscular pains. These may be severe.
The negative symptoms are represented by paralyses. The com- monest of these is the characteristic affection of the muscles of the eye, especially those innervated by the third pair of cranial nerves. The principal clinical symptoms are ptosis or drooping of the eyelids, double vision and paralysis of the muscles of accommodation. The pupils are often unequal and their reaction altered, the most common change being loss of reaction to accommodation while still reacting to light; but in rare instances the Argyle- Robertson reaction may be present. Optic neuritis is extremely rare, and never advanced. Less common are affections of the remaining cranial nerves, producing facial paralysis, difficulty in swallowing or in production of speech, etc. No portion of the nervous system is immune, and instances occur with paralysis of limbs and other parts, producing monoplegia, hemiplegia, diplegia, or aphasia. The sensory system is much less frequently affected. The deep reflexes are commonly but not invariably absent.
Morbid Anatomy. The small vessels of the brain and meninges are dilated, the congestion often being visible both to the eye and under the microscope, but the most characteristic change is infiltra- tion with small round cells of the perivascular lymph spaces, sur- rounding the capillaries. Other less constant and less conspicuous changes include degeneration of the nerve cells and destruction of neurons, proliferation of the mesoblastic cells lining the vessel walls and of the glial cells, and the occasional occurrence of haemorrhages and of thrombosis of veins. The lesions are most common in the mid-brain and basal ganglia, but any portion of the nervous system or meninges may be affected.
Prognosis. Excluding mild and abortive cases, and the so-called formes frustes, the mortality is about 33 per cent. Including all cases it is under 20 %, but the exact figure is doubtful. Deaths usually occur within three weeks from onset. The duration may be many weeks or even months. Alteration of the mental functions may be prolonged, and paralyses, aphasia and other changes have per- sisted long enough in some instances to be regarded as permanent, but when recovery takes place, it usually becomes complete.
Treatment. This ft on the general lines of treatment of acute febrile disease. Hexamine is usually administered. Netter strongly advocates the production of a local abscess by the injection of turpentine, 1-2 cc., into the thigh, but the value of this is not yet confirmed. (H. L. T.)
ENGINEERS, MILITARY (see 9.406*). In the earlier article it was pointed out that in the early days of warfare, and in Great Britain up to the wars of Marlborough, the engineers of an army were the builders of fortifications, and also the manufacturers and directors of engines of war. In 1716 the first separation of specialists occurred when the Royal Artillery was definitely formed into a separate regiment. British engineer officers, left to their more specific duties of defensive works and of military surveys, were, until 1757, frequently holders of commissions in the infantry, and it was not until the siege of Gibraltar, towards the end of the i8th century, that any nucleus of enlisted rank and file was added to the corps of officers, who by that time were called Royal Engineers. This creation of specialist branches of military engineers naturally continued with the progress of engineering in civil life, and its application to military needs. Thus, after the experience of the American Civil War in 1861-5 had brought to light the extreme value of the electric telegraph in military operations, a telegraph troop was added to the Royal
Engineers in 1870. This unit was shortly afterwards utilized by the British Post Office in connexion with civil telegraph duties, and for many years afterwards the connexion between the army and the civil department concerned was maintained in Great Britain to the great advantage of the military engineers, who by constant practice in the working of civil lines of telegraph were being prepared for this task in war. Gradually, however, the military specialties tended to develop, and the units concerned came to have a somewhat special equipment and to be divided into air-line companies (where the wires are carried on light poles rapidly erected), cable companies (where insulated cable is laid in any ground in any convenient way), and wireless.
Prior to the outbreak of the World War the signal service in the British regular army consisted of one signal squadron, 5 signal troops (for one cavalry division and 5 cavalry brigades), 6 divisional signal companies, and 4 other units. Some 20 more units were formed on mobilization, the total establishment for the Expeditionary Force being 78 officers and 2,367 other ranks. In the Territorial Force there were 5 army troops and 14 division- al signal companies, the former units being subdivided into wire- less, air-line and cable companies. In 1918 the total numbers had increased to 2,499 officers and 69,264 other ranks, exclusive of Dominion forces and those on the Indian establishment. The number of units was upwards of 400, operating at home and in practically all the theatres of war, and including despatch riders, messenger dog service, carrier pigeons, wireless motor sections, and subsections attached to field and garrison artillery. The materials were partly obtained from the G.P.O. in England, but also from sources under the direct control of the director of fortifications and works who had under him five factories for the manufacture of special wireless sets, telephones and cables. The scale of supply may be inferred from one item alone, viz., insulated cable, of which enough was sent to France in one year of the war to go 10 times round the globe. Such an immense development as this, however successfully it was carried out (and there is no doubt on this point), evidently demanded an organization of its own, and consequently, after the war, a new branch was formed called " The Royal Corps of Signals."
In like manner the British Air Service, in 1912, was separated from the Royal Engineers. The first steps to form an aerial observation corps were taken about 1878, although individual officers had taken up the subject at a much earlier period. Aerial observations and photography from balloons were carried out on active service in the Sudan and Bechuanaland in 1884-5 and throughout the South African War 1899-1902. The devel- opment of the internal combustion engine, however, in the early part of the present century, made the dirigible balloon possible, and the application of this engine to heavier-than-air machines in 1907 introduced into war a new factor of the utmost impor- tance. The Air Battalion of the R.E., which in 1911 was mainly occupied with balloons, kites and airships, and had made some progress in developing the new inventions, became early in the following year the military wing of the Royal Flying Corps.
To some extent the work of submarine mining, brought to great perfection by the R.E. in connexion with coast defence, in the closest cooperation with garrison artillery and defence electric lights, belongs also to this category. It was abolished, in so far as its connexion with the army is concerned, in 1905, its work being handed over to the Royal Navy. In this transfer, however, the cooperation between guns, lights and mines could not be carried out as before, and the reason for the change is not that of the two other instances, viz. the great growth and importance of the branch of engineering concerned.
While, however, the growth of special branches necessitated their severance from the parent corps, the exigencies of war brought into being other branches of a nature previously unforeseen. Besides signal units, the normal composition of the R.E. before the World War included field, fortress and railway companies, with field squadrons for the cavalry, and bridging trains with armies. Although these still continued, with numbers enormously increased, other special branches soon began to be formed. Army troops companies (formed out of the fortress
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