326 History of Animal Plag7ies. 



every light, this evacuation appears to be injurious in the murrain. For 

 if there can be a case supposed where it might tend to reheve against a 



is so considerable and the fever so high that nature is obstructed and cannot expel 

 the morbid matter, and, whenever such symptoms are apprehended, prudence will 

 require bleeding to prevent this coming on, according to the constitution, strength, 

 or age of the beast.' But I must dissent from the doctor as to his opinion that 

 there are any cases which admit of a rule to be laid down for bleeding the cattle in 

 the murrain. That inflammation does ever obstruct natitre so that she cannot expel 

 the morbid matter is a mere hypothesis, and, perhaps, might easily be shown to be 

 such, as it is not consistent with tlie known principles of physiology ; I shall, how- 

 ever, waive any discussion of that kind here. It is sufficient to deny that any such 

 inflammation is found in the course of this disease, as no strong signs of any appear 

 but the shivering and heat in the earlier part of the second stage, which denote an 

 eruption, and are, as above-mentioned, enumerated by the doctor himself among 

 the prognostics of recovery ; or the violent fever, which follows the attack of the 

 disease on the viscera in the very last period, and is, consequently, always a fatal 

 symptom. But admitting there were cases when it might be beneficial to bleed the 

 beasts in this distemper, with a view to prevent the coming on of too much inflam- 

 mation, or the consequences of it when subsisting, how are they to be certainly 

 distinguished in practice ? Few physicians would agree with each other in settling 

 precise diagnostic marks of this indication. How then are untaught owners of 

 cattle, on whom the task of judging on this matter must depend in the general exe- 

 cution of ,it, to determine on a point of so complex and nice a nature ? On what, 

 according to Doctor Layard's intimation, is to be grounded the apprehension of the ' 

 symptoms when i)7-iidence zvill regit ii-e bleeding to prevent this coming on? Some an- 

 swer to that diificulty is, indeed, given in another passage of his essay below, page 

 65, where he declares, ' If a beast be full-grown and fleshy, if a cow big with calf 

 and of such colour as denotes strong fibres, then take away two quarts of blood 

 from the neck. From a strong yearling calf, one quart : and so on in proportion 

 to age and strength, but neither weakly nor poor thin cows, especially white ones, 

 are to be bled so much, if at all.' But in the third chapter, where he treats of the 

 prognostics, he enumerates these circumstances among the marks by which it may be 

 discerned what beasts are least in danger of being attacked by the contagion and 

 suffering violently from it, all which marks are, in fact, the appearance of strength, 

 though he has not directly said so. Now, if strength be the preservative from the 

 contagion and its effects, what is the consequence of bleeding those which bear • 

 such marks but, in fact, reducing them to the same state with the others which 

 want this strength, or, in other words, rendering them equally unable to resist the 

 effects of the contagion ? Is not this setting up of art founded on vague principles for 

 the sake of accommodating practice to the notions and hypotheses of darling writers, 

 in opposition to the clear dictates of reason suggested by observation on facts. In 

 chapter the eighth, speaking of the means to prevent infection, he is led round 

 again to truth by the force of such observation. For there he very justly acknow- 

 ledges the real fact that ' Bleeding and purging the cattle, so far from being of 

 use, has not prevented the disease, but rather the symptoms have been more violent 

 in some who were bled and purged.' The reason is obvious ; because, being weak- 

 ened, the beasts were less able to resist the contagion. But has tlie bleeding less 

 effect in weakening the subject when performed after the infection has taken place 

 than it had before ? Surely it has not. This was delivered candidly from observ- 



