156 THE ANIMAL PARASITES OF MAN 



thirst). The temperature may reach 41 C or more. At the same time 

 there is sensitiveness in the region of the spleen and enlargement of 

 that organ. After four to six hours an improvement takes place, and 

 with profuse perspiration the body temperature falls rapidly, not 

 often below normal. After the attack the patient feels languid, but 

 otherwise well until certain prodromal symptoms (heaviness in the 

 body, headache) which were not noticed at first, denote the approach 

 of another attack of fever, which proceeds in the same way. 



The intervals between the attacks are of varying length which 

 permit of a distinction in the kinds of fever. If the attacks intermit 

 one day, occurring on the first, third and fifth days of the illness 

 and always at the same time of day, it is termed febris tertiana ; if 

 two days occur between fever days, it is called febris quartana. In 

 the case of the fever recurring daily, later writers speak of typical 

 febris qnoiidiniid. But a quotidian fever may arise when two tertian 

 fevers differing by about twenty-four hours exist at the same time 

 (febris tertiana duplex). The patient has a daily attack, but the fever 

 of the first, third and fifth days differs in some point (hour of 

 occurrence, height of temperature, duration of cold or hot stage) 

 from the fever of the second, fourth and sixth days. Similarly, 

 two or three quartan fevers which differ by about twenty-four hours 

 each may be observed together (febris qnartaua duplex or triplex] ; 

 in the latter case the result is also a quotidian fever. 



Two kinds of tertian fever are differentiated a milder form 

 occurring especially in the spring (spring tertian fever), and a more 

 severe form appearing in the summer and autumn in warmer 

 districts, especially in the tropics (summer or tnitnmn fcrcr, febris 

 cestivo-autumnalis, febris tropica, febris peruiciosa). The latter often 

 becomes a quotidian fever. 



All the afore-mentioned infections are termed acute. They' are 

 distinguished from the very different chronic malarial infection by the 

 frequent occurrence of relapses, which finally lead to changes of 

 some organs and particularly of the blood. The relapses are then 

 generally marked by an irregular course of fever. 



The term masked malaria is used when any disturbance of the state 

 of health of a periodic character shows itself and disappears after 

 treatment with quinine. 1 Generally it is a question of neuralgia. 



That intermittent fever was an infectious disease, although not one which was 

 transmitted direct from man to man, had been assumed for a long time. Therefore 

 it was natural, at a time when bacteriology was triumphing, to look for a living agent 

 causing infection in malaria, which search was, seemingly, successful (Klebs, 

 Tomasi-Crudeli, 1879). Hence it was not surprising that the discovery of the 



1 Quinine is still almost exclusively the remedy used in the treatment of malaria. It is 

 prepared from the bark of the cinchona tree. This important remedy was introduced into 

 Europe in 1640 from Ecuador by Juan del Vego, physician of the Countess del Cinchon. 



