456 PRACTICE OF PHYSIC. 



ease : but there are many instances of it occurring in persons 

 considerably advanced in life ; though it is probable, that the 

 farther that persons are advanced in life, they are the less liable 

 to be affected with this contagion. 



MCCCCIV. The disease commonly comes on with the ordi- 

 nary symptoms of a catarrh arising from cold ; and often, for 

 many days, keeps entirely to that appearance ; and I have had 

 instances of a disease, which, though evidently arising from the 

 chincough contagion, never put on any other form than that of 

 a common catarrh. 



This, however, seldom happens ; for, generally in the second, 

 and at farthest in the third week after the attack, the disease 

 puts on its peculiar and characteristic symptom, a convulsive 

 cough. This is a cough in which the expiratory motions pecu- 

 liar to coughing are made with more frequency, rapidity, and 

 violence, than usual. As these circumstances, however, in dif- 

 ferent instances of coughing, are in very different degrees, so no 

 exact limits can be put to determine when the cough can be 

 strictly said to be convulsive ; and it is therefore especially by 

 another circumstance that the chincough is distinguished from 

 every other form of cough. This circumstance is, when many 

 expiratory motions have been convulsively made, and thereby 

 the air is in great quantity thrown out of the lungs, a full in- 

 spiration is necessarily and suddenly made, which, by the air rush- 

 ing in through the glottis with unusual velocity, gives a peculiar 

 sound. This sound is somewhat different in different cases, but 

 is in general called a Hoop, and from it the whole of the disease 

 is called the Hooping-cough. When this sonorous inspiration 

 has happened, the convulsive coughing is again renewed, and 

 continues in the same manner as before, till a quantity of mu- 

 cus is thrown up from the lungs, or the contents of the stomach 

 are thrown up by vomiting. Either of these evacuations com- 

 monly puts an end to the coughing, and the patient remains 

 free from it for some time after. Sometimes it is only after 

 several alternate fits of coughing and hooping that expectoration 

 or vomiting takes place ; but it is commonly after the second 

 coughing that these happen, and put an end to the fit. 



MCCCCV. When the disease, in this manner, has taken its 

 proper form, it generally continues for a long time after, and 



