4 
lomata are due to a larval Habronema, this result is not very 
122 
8: : : 
Lewis concludes that the probability is that the virus 
which causes the lesions “is normally a habitant of the 
amps." 
is necessary, or the appearance of the causative agent In th 
horse is an accidental phenomenon. . . ." These conclu- 
sions actively support the above hypothesis, for if the lesioni v 
due to a larval //abronema, the presence of an intermedia 
host or carrier is necessary, and, moreover, the appearance 0 
the causative agent in the horse is, as far as we know, 4? 
accidental phenomenon. 
“Swamp cancer” occurs in horses in the field, but ues 
these animals are brought in and placed on “hard food, adi 
informs us, the tumours gradually disappear. If the gran" 
surprising, for in this case there is present no virus or muc 
organism capab ti 
to transmit the disease from horse to 2°" 
taken as very strong evidence against the probability 
