TRYPANOSOMES, TRYPANOSOMIASIS, AND SLEEPING SICKNESS 91 
the posterior cornua and small-celled infiltration around a blood vessel in the lumbar 
region ot a horse naturally infected with the malady (it had shown paraplegic 
symptoms). Neuritis has been described in animals infected with T. equiperdum. 
From these facts one must conclude that the lesions in the brain, cord, and 
organs can be produced by the trypanosomes. We have only found these changes 
occurring in animals infected with the parasite for some time, and in whom there 
were evidences of the duration of the disease, such as anaemia, loss of weight, etc. 
It would, therefore, appear that only in the chronic infected animals do the lesions 
occur. 
In the ' trypanosome fever' case we have not found the same appearances in the 
brain and spinal cord as in our sleeping sickness cases, probably because the disease 
was not long enough established to produce the changes around the vessels of the 
nervous centres. 
