rufescens, and the worm which has recently been described as the Pseudalius 

 ovis, a long thread-like worm which is found coiled up beneath the pleura in 

 small cavities, or inclosed in little masses of calcareous matter. Strongylus 

 rufescens is distinguished from the Strongylus filaria by its small size, and red or 

 yellow tint. It is sometimes found in association with the filarise in the bronchial 

 tubes. Pseudalius ovis has often been described, but its life history is not 

 satisfactorily made out. Dr. Crisp many years ago referred to it as a gordian 

 worm. Other writers have taken it for a species of strongle, and lately 

 A. Koch suggested that it is the embryo form of Strongylus rufescens, a view 

 which seems to be negatived by the fact that it is much larger than the rufes- 

 cens, and certainly does not agree with it in the arrangement of the internal 

 organs. No special importance is to be attached to the presence of one variety 

 of strongle more than another from the point of view of cure and prevention, 

 nor, indeed, in regard to the symptoms which the infested animals exhibit. 



Sheep and calves suffering from parasitic bronchitis fall off in condition, and 

 are subject to an irritating dry cough, a symptom which gives the common 

 name husk to the disease. 



Emaciation, which is the most prominent indication in the affection, is the 

 result of the blocking up of the air tubes and cells by the worm, their eggs and 

 embryos, and by the exudation into the minute lung structure consequent on 

 the irritation which is set up. 



In some cases of parasitic bronchitis in older cattle, it has been found, on 

 post-mortem examination, that all the adult worms had migrated or been 

 expelled from the air tubes. The least pressure applied to a portion of lung 

 caused the exudation of a thick purulent fluid in small drops, and under the 

 microscope it was seen that the puss-like exudate was composed of masses of 

 eggs in various stages of development, many of them containing living embryos, 

 and free embryos which were moving about with great activity. 



It is important to note that the absence of the thread worms from the bron- 

 chial tubes does not justify a conclusion that the disease did not exist. On the 

 contrary, the condition of things above described shows that in the most 

 advanced cases of parasitic bronchitis there may not be any parasites visible to 

 the unaided eye, although the microscope will exhibit them in masses. 



Owing to the serious losses which occur among calves and lambs, and 

 occasionally among adult cattle and sheep, from the ravages of strongles, 

 stockowners have for many years past been anxiously asking for information as 

 to the causes of the disease and the best means of cure and prevention, hitherto 

 without much success. 



Causes may be summed up in a few sentences. The embryos which are, or 

 for years have been, distributed over pastures in which cattle and sheep have 

 been grazed retain their vitality for a long period, even under extreme con- 

 ditions of climate. In wet seasons they flourish, and it is always observed that 

 the occurrence of rain at almost any period of the summer and autumn is 

 followed by outbreaks of husk. Some pastures which are low and wet are 

 dangerous at all times during the grazing season. 



Prevention of the disease implies removal from the pastures when the 

 embryos of strongles are likely to be present ; but this is in many cases an 

 impossible remedy, there being no feeding grounds on the farm free from them. 

 Perhaps top dressings of salt might be beneficial in one way, but it is to be 

 feared that the use of that agent in sufficient quantity to kill the embyro worms 

 would be very prejudicial to the herbage. 



