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larval stage of Habronema muscae, as observed by Ransom in 

 Musca domestica. 



After discussing the findings of the various authors, 

 Railliet comes to the conclusion that the Nematode of "sum- 

 mer sores" is none other than a larva of Spiroptera of the 

 genus Habronema. His general conclusions are as follows : — 



1. The parasite of verminous dermatitis is an embryo 



or a larva of Habronema, which it is rational to 

 ascribe to one of the three species of the genus 

 living in the stomach of the horse. 



2. The clinical forms of the affection vary in a certain 



measure with the stage of evolution of the parasite 

 and with the climate. 



3. It is probable that the infection of the horse occurs 



from without inwards by contact with manure, 

 which harbours the embryos of Habronema rejected 

 with the excrements, and that these embryos evolve 

 in the skin as they do normally in the body of 

 the fly. 



4. It is possible also that the larvae escape from the 



proboscis of the fly in contact with the sores. 



More recently van Saceghem (1917) published a summary 

 of some observations he had made on "granular dermatitis" 

 as it occurs in equines at Zambi, Lower Congo. He found that 

 the condition occurs only in animals kept in stables. The 

 bedding was changed and the dung removed regularly from 

 these stables. 



The disease is never localized in the hindquarters, but 

 always in the fore quarters, on the legs, and the inner canthus 

 of the eye. Lesions in other situations are rare. Equines 

 which are allowed to live at liberty never present the disease. 

 In a stable where several horses were affected with "summer 

 sores" he found that 20 per cent, of Musca domestica were 

 infested with a Nematode larva 2*5 mm. long by 65 /x broad. 

 The larva possessed an elongated, pointed, anterior extremity, 

 and a blunt posterior end studded with bristles. The larvae 

 showed no longitudinal striations. 



The larvae found in the sores were 50 ju broad, and showed 

 marked longitudinal striations. The lesions usually show a 

 large number of calcified larvae and a few living ones. He 

 says that there is thus a massive infection at a single point, 

 and it is not very probable that these larvae are all conveyed 

 during one short period of time to the same point. 



In a later communication, van Saceghem (1918) records 

 the results of some experiments, and concludes that flies are 

 the vectors of the Habronema larvae, and that the larva found 



