ANAESTHESIA. 45 



minutes. By using a special apparatus, by means of which abso- 

 lutely pure chloroform vapour, without admixture of air, was 

 administered, death was produced in one and a half minutes. The 

 heart's action continued for several minutes after respiratory arrest. 

 Moller, who employs chloroform exclusively, has administered it to 

 many hundreds of horses without a single accident. 



As a basis for investigation, Moller noted in each of his cases the 

 time required to produce surgical anaesthesia, the amount of 

 chloroform used, the breed, age, sex, and weight of the animal. The 

 following is a resume of the more important results. In a series of 

 126 cases (31 stallions, 38 mares, and 57 geldings) anaesthetised with 

 chloroform, the corneal reflex was abolished in an average period of 

 20 minutes by the administration of an average quantity of 28 fluid 

 drachms of chloroform ; the quantity per unit of body-weight was 

 1 : 4000 ; anaesthesia usually lasted about 20 minutes. 



Whilst in one to two years old animals 4 to 5 drachms of 

 chloroform usually produced anaesthesia in 7 to 8 minutes, the 

 shortest time observed in full-grown horses was in one case 8 minutes, 

 in one case 9 minutes, and in two cases 10 minutes. Twelve of the 

 above 126 horses required 30 minutes, and four from 30 to 40 

 minutes. In stallions the average period was 18, in mares 19, and 

 in geldings 22 minutes. The stallions on an average consumed 30 

 drachms of chloroform ; 7 horses (3 stallions, 2 mares, and 2 

 geldings) took, however, less than 12| drachms ; on the other hand 

 18 (5 stallions, 4 mares, and 9 geldings) required 38 fluid drachms, 

 or over. One gelding received 60 fluid drachms, and an English 

 thoroughbred 62| fluid drachms. The average age of the stallions 

 was 5, of the mares 9, and of the geldings 7 years. 



It is worth noting that the quantity of chloroform used depends 

 partly on the method of administration. Apart from the quantity 

 lost by leakage or evaporation, less is required when administration 

 is slow than when it is rapid. The quantity used, therefore, often 

 stands in inverse proportion to the pre-anaesthetic period. 



Breed seems to have little relation to the anaesthetic influence of 

 chloroform ; it neither affects the quantity required nor the pre- 

 anaesthetic interval to any appreciable extent. On the other hand, 

 it was noted that geldings on an average required considerably 

 more chloroform than stallions and mares. 



Twenty-eight horses received subcutaneous injections of lh grams 

 morphine before administration of chloroform. In these cases the 

 average quantity of chloroform used was 24 fluid drachms, and the 

 time interval before complete anaesthesia 15J minutes. 



