17 



the port of the eastern coast, of S. albopicta {scutellaris), which occurs, 

 though less abundantly than the former, in hollows in trees, or in 

 water in wooden receptacles, either natural or artificial. The only 

 species of Ctdex which occurs in C. argenteo-pimctatus, which is not 

 numerous, the permeabihty of the sandy soil rendering stagnant 

 pools impossible. Anophelines have also almost completely disappeared 

 following upon the drainage operations carried out in connection 

 with building. Stegomyia on the other hand find ideal conditions 

 in the town and breed in alarming numbers. A fever which is probably 

 dengue causes severe epidemics, and must be transmitted by S.fasciata, 

 since Phlebotomus has not been observed in the town. 



Stockman (S.). Louping-ill. — Jl. Comp. Path. TherapeuL, London, 

 xxxi, no. 3, 30th September, 1918, pp. 137-193, 10 figs. 



While previous experimental evidence, recorded in an earlier paper 

 by the author, was against the view that louping-ill in sheep might 

 be carried by ticks, it was realised that the possibilities of this theory 

 had not been exhausted, and further experiments have recently been 

 carried out. These prove that larvae of Ixodes ricinus from females 

 which as adults engorged on affected sheep can give rise to a highly 

 febrile and sometimes fatal disease in other sheep, when put to feed 

 upon them in very large numbers, and that adults fed as nymphs 

 on affected sheep may have the same effect. The apparently negative 

 results recorded in an earlier paper may have been due to the fact 

 that only a small proportion of ticks become carriers of infection. 

 Ticks allowed to engorge upon sheep imdergoing experimental inocula- 

 tion were found capable, after moulting to their next stage, of causing 

 the disease in other sheep upon which they were put to feed. It is 

 evident that the infective agent can be transmitted from the female 

 ticks through the eggs to the next generation of larvae, but it is not 

 conclusively proved that ticks in their nymphal stage can transmit 

 the disease. It follows almost certainly from the fact of ticks trans- 

 mitting the infection that the infective agent is a protozoan parasite. 

 The blood of a sheep that has recovered from the disease produced 

 either by inoculation or in natural manner does not continue to be 

 infective by inoculation to others, and it is therefore unlikely that 

 ticks can infect themselves from such animals. 



The cure, prevention and eradication of the disease is discussed. 

 Drugs that have proved more or less successful in treating similar 

 diseases were tried, but were invariably ineffective. It is possible, 

 however, that an anti-serum with curative properties may be prepared, 

 and investigations in this direction are being carried on. Serum 

 treatment is not promising in dealing with this class of disease. 

 Prevention of the disease by inoculation in the field is rather more 

 promising and arrangements are being made for practical tests of this 

 method. Eradication of ticks would reduce louping-ill to a negligible 

 factor. The seasonal incidence arises from the fact that ticks infected 

 on sheep in the spring have hatched out or moulted by the autumn 

 and are capable of infecting other sheep ; those ticks infected in the 

 autumn are in a position to infect other sheep in the following spring. 

 The isolated cases that may occur at other times are due to infected and 

 fasting ticks that previously failed to obtain a vertebrate host. The 

 (C530) B 



