344 CANINE MALARIA 
The period of incubation after direct inoculation is about three days. 
When it follows exposure to the infected tick it is reported to be 
between ten and twenty days. 
Symptoms. Two distinct forms have been described: the acute 
which is nearly always fatal, and the chronic which often terminates 
in recovery. In the acute form the dog is dull, drowsy and refuses 
food. It may be thirsty. The temperature is high (104° F.) but 
after two or three days it drops to subnormal. Icterus is not constant 
and the hemoglobinuria is not always present. The blood is pale 
and it coagulates slowly. The red corpuscles are reduced to 2,000,000 
per cubic millimeter or below. The polynuclear leucocytes are 
increased in number. In the acute cases death nearly always occurs 
in from three to six days. 
In the chronic cases the fever remains high for from 36 to 48 hours, 
when it returns to normal. The anemia is the most constant mani- 
festation. The mucose become pale and the appetite is poor. The 
symptoms persist for from three to six weeks. Recovery frequently 
takes place. 
The duration in fata] cases is from 3 to 6 days. In chronic cases it 
may be several weeks. 
Morbid anatomy. The mucous membranes are pale and the sub- 
cutaneous tissue and fat more yellow than normal. The spleen is 
3 or 4 times the normal size. The liver is engorged with blood which 
is heavily charged with parasites. The gall bladder is distended with 
greenish bile. The mucosz of the digestive tract are slightly, if at all, 
changed. The kidneys are congested, often sprinkled with petechize 
or ecchymoses. The capsule is easily removed. The parasites are 
found in the blood in the early stages of the disease. They are more 
numerous in the capillaries than in the heart blood. 
The lungs are in some cases edematous. In all young animals one 
finds edema of the lungs with blood stained mucoserous substance: in 
the trachea and bronchioles. The lymphatic glands are rarely if ever 
altered in appearance. 
The central nervous system presents nothing of note, except a 
slight congestion of the meninges. 
The histological study of the lesions shows that the tissue changes 
start from greatly engorged capillaries. In these vessels containing 
masses of blood, a large part of the red corpuscles contain the parasite. 
