C. Warburton 337 
are, I believe, entirely due to the introduction of bacteria.... In some instances no further 
symptoms have been noticed except perhaps a slight thickening of the skin and a gluing 
together of the hairs. In other cases there has been intense irritation and a dermatitis has 
been set up.... Sometimes the inflammation is more extensive, and large oedematous areas 
have been noticed, extending into the deep tissues. In the outbreaks of previous years 
a number of bad sloughs have occurred, some of them on the upper part of the udder, and 
on the thighs. Other parts where serious lesions have been encountered are in the line 
from the point of the ischium and the patella, and some few patches on the flanks, becoming 
more numerous until they reach the sides of the sternum, under the elbow. Some quite 
large lesions have been noticed on the tail.... Seeing that the penetration of the larvae 
produces a definite disease, I would propose the name ‘hypodermal rash.’ 
In the case of H. bovis, Carpenter, Hewitt and Reddin 1 noticed a rash of 
small pimples on the day following penetration, but the lesions were not 
serious. H. lineatum might be expected to be much more formidable in this 
respect, because of the number of larvae which must enter near the same spot. 
It has been suggested by several writers that anthrax germs may thus find 
an entrance to cattle. 
Des Gayets and Vaney, and Jensen, have especially studied the lesions 
caused by the larvae in the oesophageal wall, and have met with cases of 
stenosis of the gullet caused by them. 
Lesions in the spinal canal are difficult to verify, but there is little doubt 
that at this stage of their journey considerable harm may be done to cattle 
by Hypoderma larvae. Signs of inflammation in the cord are generally notice¬ 
able in their neighbourhood, and Moussu told Hadwen (1916, p. 11) that he 
had seen nervous symptoms in cattle which he attributed to this cause. 
There are indications that the first appearance of the maggots in the dorsal 
integument is the occasion of especial constitutional disturbance. Mr K. J. 
Mackenzie tells me that he has often observed a sudden rise of temperature in 
animals at the time when warble tumours first become recognisable to the 
touch as small hard swellings, and that the temperature falls as suddenly 
after the formation of the external aperture. It is a common experience that 
animals that have done badly during the winter and early spring, and then 
develop many warbles, pick up at once after the warble season. 
There is an acute but usually transient and not fatal cattle disease prevalent 
in the spring in some localities and known as rose fever, which has recently 
been investigated by Brodersen. There is extensive oedema, especially on the 
eyelids, muzzle and lower jaw, and often on the udder and in the region of 
the anus. The disease has usually been attributed to mistakes in feeding, 
but Brodersen finds that it frequently follows immediately on the operation 
of expressing Hypoderma larvae, and he thinks it due to the toxic effect of 
grubs crushed beneath the hide. In this connexion Jensen recalls his experi¬ 
ments of 1903, when he injected under the skin of a calf the extract made in 
sterile salt solution, of two larvae taken from the gullet of a cow and obtained, 
about an hour later, symptoms characteristic of rose fever. 
1 Journal xv. 1916. 
