The Rot in Sheep. 



19 



and prevented the sheep from having access to the swampy 

 border that surrounded it, and the rot entirely ceased." 



It will be seen that the cessation of the disease from such 

 proceeding at once negatives the idea propounded with regard 

 to miasm. If the pond had been thoroughly drained, the water 

 being entirely removed therefrom, and the general condition of 

 the soil thus improved, we can understand that miasmatic vapours 

 would have ceased to arise from it ; but the pond still remaining 

 as a pond, with its swampy border, miasmatic matter would be 

 produced equally as well when it was enclosed with an ordinary 

 fence as when it was open to the entire area of the field. 



The theory of miasmata being the cause of rot has already 

 been shown to have originated with Dr. Harrison in 1804, 

 although long antecedent to his time the injurious effects of 

 " bad air " had been vaguely alluded to. We may further 

 remark that the miasmatic theory was revived by Davy in his 

 essay on ' Bane,' published just before the writings of Youatt. 



D. Price, previously quoted from, rightly observes that 

 " many objections might be urged against this theory, however 

 plausible it may appear. I shall here content myself, however," 

 he says, " with stating a fact recorded by the learned and 

 ingenious Dr. George Pearson, in a letter to Arthur Young, 

 Esq., which powerfully militates against the hypothesis in 

 question ; " and he adds, " as this communication is valuable, 

 not only for the fact it contains, but on account of the philoso- 

 phical spirit which pervades it, I deem no apology necessary for 

 presenting it to my readers in Dr. Pearson's own words : — 



" The paper lately written by my friend Dr. Harrison on the rot of sheep 

 is very valuable indeed for the great number of tacts with which it is enriched. 

 These facts are of various applications for the economist, the agriculturist, the 

 breeder, and the practitioner of physic. The subject of the rot in general, I 

 am persuaded, is in very able hands for further investigation, as Dr. Harrison's 

 opportunities, from his residence, are most favourable. Hence, if I had leisure, 

 I should not be inclined to occupy myself in this inquiry ; but it may, perhaps, 

 be the means of eliciting or of confirming truth to state an apparent objection 

 to the ingenious author's conclusion — ' that the rot is occasioned by the same 

 morbific agent which occasions intermittent and remittent fevers.'' This mor* 

 bific matter is called miasmata pallidum in the schools of physic, and those 

 miasmata are engendered especially in marshy and boggy grounds or fens, 

 particularly in the spring and autumnal season. In some of the marshes of 

 Kent intermittent fevers affect a great proportion of the inhabitants ; and even 

 persons in the neighbourhood, although living on dry chalky lands, where 

 these disorders never appear if remote from the low grounds, unless by im- 

 portation. I was lately in Chitney Marsh, on the Med way, near the Isle of 

 Sheppey, one of the most prolific situations for agues to be found in the king- 

 dom. It is famous also for its pasturage, by which very great numbers of 

 sheep are fed. Observing the sallow, and indeed cadaverous, countenances of 

 the inhabitants, most of whom were ill or were recovering from agues, I was 

 led to inquire into the health of the slur]). Besides the evidence of th<> line 

 healthy condition of these animals I obtained that of the shepherd, who had 



