678 



INFECTION AND IMMUNITY. 



General 



its non-flagellated end. The failure to find any 

 distinctive difference between this organism and 

 T. neprevi (T. gambiense) is an additional point 

 in favor of the unity of trypanosomatic fever and 

 sleeping sickness. 



TRYPANOSOMIASIS IN ANIMALS. 



On account of the prevailing general interest in the 

 subject, the more important trypanosomatic infections 

 in animals and the corresponding parasites will be 

 sketched briefly. 



Musgrave and Clegg speak of certain general symp- 

 Symptomat- toms which are common to surra, nagana, mal de caderas 

 oiogy. an( j 0^!^ as follows: "After an incubation period, 

 which varies in the same class of animals and in those of 

 different species as well as with the conditions of infec- 

 tion, and during which the animal remains perfectly 

 well, the first symptom to be noticed is a rise of tem- 

 perature, and for some days a remittent or intermittent 

 fever may be the only evidence of illness. Later,, the 

 animal becomes somewhat stupid; watery catarrhal dis- 

 charges from the nose and eyes appear; the hair becomes 

 somewhat roughened and falls out in places. Finally, 

 the catarrhal discharges become more profuse and the 

 secretion more tenacious and even purulent; edema of 

 the genitals and dependant parts appears; a staggering 

 gait, particularly of the hind parts, comes on and is fol- 

 lowed by death." 



Infectious- The incubation period varies from a few to several 

 days. Pronounced anemia develops, the method of de- 

 struction of the erythrocytes being unknown. Lymphatic 

 enlargement is the rule, and during the incubation period 

 the parasites probably undergo great proliferation in the 

 lymph glands. It is somewhat characteristic that mas- 

 sive invasion of the blood streams occurs periodically. 

 With a paroxysm of fever their numbers increase in the 

 blood, and during the intermission they decrease and 

 may be so few as not to be found microscopically. Even 

 when few or no parasites are found in the circulation, 

 however, the blood usually is infectious for other ani- 

 mals. During the intermissions it is possible that they 



