244 SMALL-POX. 



tinctly produced and guarded from all friction. If the general character 

 of the pustules is considered, it will be observed, that, while some of them 

 are in a state of serous secretion, others will only have begun to appear. 



The eruption terminates when desiccation commences in the first pus- 

 tules ; and, if some red spots show themselves at that period of the malady, 

 they disappear without being followed by the development of pustules, 

 They are a species of abortive pustules. After the desiccation, the skin 

 remains covered by brown spots, which, by degrees, die away. There 

 remains no trace of the disease, except a few superficial cicatrices on 

 which the hair does not grow. 



The causes which produce the greatest variation in the periods of the 

 eruption are, the age of the dog, and the temperature of the situation 

 and of the season. The eruption runs through its different stages with 

 much more rapidity in dogs from one to five months old than in those 

 of greater age. I have never seen it in dogs more than eighteen months 

 old. An elevated temperature singularly favours the eruption, and also 

 renders it confluent and of a serous character. A cold atmosphere is un- 

 favourable to the eruption, or even prevents it altogether. Death is 

 almost constantly the result of the exposure of dogs having small-pox to 

 any considerable degree of cold. A moderate temperature is most favour- 

 able to the recovery of the animal. A frequent renewal or change of air, 

 the temperature remaining nearly the same, is highly favourable to the 

 patient ; consequently close boxes or kennels should be altogether avoided. 



I have often observed, that the perspiration or breath of dogs labouring 

 under variola emits a very unpleasant odour. This smell is particularly 

 observed at the commencement of the desiccation of the pustules, and when 

 the animals are lying upon dry straw ; for the friction of the bed against 

 the pustules destroys their pellicles, and permits the purulent matter to 

 escape ; and the influence of this purulent matter is most pernicious. The 

 fever is increased, and also the unpleasant smell from the rnouth, and that 

 of the faeces. In this state there is a disposition which is rapidly deve- 

 loped in the lungs to assume the character of pneumonia. This last 

 complication is a most serious one, and almost always terminates fatally. 

 It has a peculiar character. It shows itself suddenly, and with all its 

 alarming symptoms. It is almost immediately accompanied by a purulent 

 secretion from the bronchi, and the second day does not pass without the 

 characters of pneumonia being completely developed. The respiration is 

 accompanied by a mucous rale which often becomes sibilant. The nasal 

 cavities are filled with a purulent fluid. The dog that coughs violently 

 at the commencement of the disease employs himself, probably, on the 

 following day in ejecting, by a forcible expulsion from the nostrils, the 

 purulent secretion which is soon and plentifully developed. When he is 

 lying quiet, and even when he seems to be asleep, there is a loud, ster- 

 torous, guttural breathing. 



MANGE. 



The existence of certain insects found burrowing under the skin of the 

 human being, and of various tribes of animals, has been acknowledged 

 from the 12th century. In the 17th century correct engravings of these 

 insects were produced. On the other hand many doubted their existence, 

 because it had not been their lot to see them. In 1812, Gale's, a pupil in 



