The neurotic character of pertussis is shown not only by the laryngeal spasm, but by the violent agitation into which the child is thrown during a paroxysm. When he feels the desire to cough becoming irresistible he clutches at his mother's dress or the nearest object capable of giving sup port, and his whole body is agitated by a convulsive trembling. This agi tation is usually attributed to terror, but it is more probably the conse quence of a general nervous commotion which, carried to a higher pitch, may become a genuine convulsive seizure. A distinguished physician who was attacked by whooping-cough after middle life, in describing the ner vous agitation induced by the spasm, assured me that in the paroxysm he required all his self-control to avoid beating with his feet upon the floor. It seems, therefore, that the neurotic element of the disease is something more than a mere nervous spasm of the larynx and diaphragm. There appears to be a general agitation of the whole nervous system, which may be more or less pronounced according to the severity of the attack and the inherent susceptibility of the child.
Simpioms.—The incubation period of pertussis is difficult to ascertain on account of the uncertainty as to the exact day upon which the disease can be said to begin. It has been estimated at from two to seven days. Other observers are of opinion that it may last a fortnight.
When the disease begins we find the symptoms of catarrh of the air passages. The eyes are slightly injected, there is snuffling and increased secretion from the nose, and the child soon begins to cough. There is some fever, the temperature usually rising to 100°, and the pulse is quickened. In a day or two there may be in addition some increased rapidity of breathing. If the catarrh affect the gastric mucous membrane, there is loss of appetite and the child may be languid and mope. The symptoms resemble those of an ordinary catarrh, but their specific charac ter may be sometimes detected by noticing the unusual obstinacy of the cough. It is repeated at very short intervals, and sometimes is almost in cessant. This catarrhal stage lasts for a variable time. It may occupy only a few days or may be continued for several weeks. The symptoms usually increase in severity as the days go by. The cough becomes more troublesome, and is worse at night than in the clay. If the child is old enough he complains of a harassing tickling in the throat ; and there is often violent sneezing, with the ejection of much ropy mucus from the nose.
After a time a change in the character of the cough shows that the spasmodic stage has begun. The cough occurs in paroxysms, and has such a distinctive character that it at once betrays the nature of the child's complaint. It consists in a number of short hacks, following so rapidly upon one another as to allow of no inspiratory effort. As these continue, the child's face turns from red to purple, and seems to swell and darken at the same time. At length, when the lungs are almost exhausted of
their air, and the patient seems upon the very point of suffocation, air is at last drawn in with a long, deep inspiration, accompanied by the charac teristic "kink " or whoop. Immediately, however, the cough begins again ; and in this way the long rapid expiratory cough, the signs of imminent asphyxia, and the slower whooping inspiration may be repeated several times before the expulsion of a large quantity of thick tenacious phlegm from the mouth, and perhaps the ejection of food mixed with ropy mucus from the stomach, announces the end of the attack. The child, then, if an infant, sinks back exhausted and perspiring in his mother's arms, and if the cough do not return immediately, usually falls into a heavy sleep. An older child seems a little languid, but if the paroxysm has not been severe, may return quickly to his amusement. If, on the contrary, the spasm has been prolonged, he may seem dull and confused for a time, and may complain of headache.
During the fits of coughing the pulse becomes very rapid, and is almost uncountable. If we listen to the back at this time we hear some slight wheezing in the large air-tubes during the expiratory cough ; but during the long-drawn inspiration any slight vesicular sound which might be heard is covered by the noise of the whoop. In the intervals of the cough auscultation in an uncomplicated case merely reveals a few large bubbles Mixed up with dry wheezing sounds scattered about the lungs.
When the paroxysms are violent they are a cause of great distress to the patient. This is well shown by the efforts a young child will make to keep them back. He may be noticed, while on his mother's lap, to hold his breath and sit perfectly still in the hope of repressing the cough. When he feels that the impulse is getting beyond his control his face becomes congested, his brows contract, and sweat breaks out on his forehead ; and as the convulsive expiratory efforts begin, he clutches at his mother's dress and often trembles all over with nervous agitation. During the paroxysm the straining may produce rupture in a child predisposed to hernia ; and haemorrhage from the intense congestion induced is a common symptom. The bleeding may take place from the eyes, the ears, the nose, the mouth, and sometimes from the lungs. Cracks about the lips and sore places on the gums almost always bleed during the fits of coughing. Epistaxis is very common. When haemorrhage occurs from the nose the blood does not always flow forwards through the nostrils ; often it passes backwards through the posterior naves into the throat. It may be then swallowed and discharged as black matter by stool, or be vomited after the next at tack of cough and cause great alarm. In other cases the blood irritates the glottis and induces a fresh paroxysm. It is then expelled with the cough and is supposed to come from the lungs.