"gbub in the head." 275 



winter and early part of the ensuing spring, abandons them 

 as the -warm weather advances. It crawls down the nose, 

 again producing great irritation and excitement; drops on 

 the ground; rapidly burrows -into it; assumes the form of a 

 chrysalis; and finally again hatches forth a perfect fly. 



Many French and English writers consider these larvse, 

 while in the heads of sheep, the causes of most serious evils 

 and of frequent death. On the other hand, Mr. Bracy Clark 

 and Mr. Youatt are not only disposed to doubt this, but they 

 even suggest that these parasites may be placed where they 

 are for the benefit of the sheep, particularly those in high 

 condition — ^ to save them from determination of blood to the 

 head by establishing counter irritation ! 



This is as far-fetched as a conclusion, as is the reasoning 

 on which it is founded. Mr. Tpuatt declares : — " It is incom- 

 patible with that wisdom and goodness that are more- and 

 more evident in proportion as the phenomena of nature are 

 closely examined, that the destined residence of the oestrus 

 ovis should be productive of continued inconvenience or 

 disease." * Had Mr. Youatt forgotten that the " destined 

 residence " of the scab acarus, of the tick, of the common 

 maggot, etc., are all productive of inconvenience, disease and 

 death to the sheep? 



If a sheep dies in the spring of the year, fat or poor, 

 suddenly or lingeringly, with one or another set of symptoms, 

 the popular belief generally traces the malady to "grub in the 

 head." It is the convenient name which covers all the 

 unknown fat&,I maladies of that season of the year. This 

 probably arises from the fact that on making what may be 

 termed the farmer's autopsy — ^viz., on splitting open the body 

 and head of the dead sheep with an axe — the most striking 

 deviation, if not the only one, from what is supposed- to be 

 the natural situation of things, which is discovered in the five 

 minutes scrutiny, is a quantity- of large, fat, ill-looking worms 

 in the cavities of the head: and our rapid practitioner at once 

 decides that these are cause enough for any disease! His 

 theory is that the " grub " borps ^through the walls which 

 separate the nasal cavities or the sinuses from the brain, and 

 that they produce death by attacking the latter organ. I 

 have been triumphantly shown the cribriform plate of the 

 ethmoid bone (see 11, in Fig. on page 273,) with its natural 

 perforations for the passage of the olfactory nerve, in proof 



• Youatt on Sheep, p. 308. 



