1895.] on the Antitoxic Serum Treatment of Diphtheria. 441 



1 or 2 c.c. can be given at the first injection. This is followed within 

 24 hours by a local swelling at the seat of injection, about the size 

 of the palm of the hand, and the temperature may rise 1° or 2° F. 

 (J° to 1° C), otherwise the general health of the horse does not 

 seem to suffer. He eats well, and unless regularly exercised may 

 become very lively ; of this we have had ample evidence during the 

 recent frost and snow, when it has been unsafe to give much exercise 

 to horses that are not very sound in limb, and as a result they have 

 been very fi esh indeed. As soon as the swelling has disappeared 

 and the temperature has receded to the original level, a somewhat 

 larger dose is given ; the same process is repeated time after time 

 (the dose being gradually inert ased to bring about the same amount 

 of swelling and rise of temperature) for about three months, or until 

 such time as the requisite amount of immunity is acquired, i. e. until 

 the antifr xic action of the blood is sufficiently marked. That there 

 is a gradually increasing immunity is evidenced by the fact that 

 enormously large doses of the toxine in the later stages of the 

 treatment produce even less local and constitutional disturbance 

 than was observed after the first few injections of comparatively 

 small quantities. 



Tie blood is now drawn off from the jugular vein of the immunised 

 horse l>y means of a metal cannula or tube to which is attached an 

 indiarubber tube ; these are first thoroughly boiled, in order that no 

 living micro-organisms of any kind may remain on or in them, and 

 the skin of the horse is carefully cleansed with some antiseptic lotion. 

 The indiarubber tube leads the blood into a carefully sterilised 

 flask or vessel provided with a double paper cap, a well-fitting 

 cotton-wadding plug or a glass-stopper. The vessel when filled is 

 placed in an ice-safe until the solid part, the clot, is completely 

 separated from the fluid — the serum. From each gallon of blood 

 about 11 to 2 quarts of serum is expressed, though this varies 

 considerably in different casas, and according to the time that the 

 separation is allowed to continue (24 to 48 hours). This serum, a 

 limpid straw-coloured fluid, is carefully decanted under strict anti- 

 septic precautions, and, mixed with carbolic acid or camphor, is 

 stored in small phials, each of which contains about a sufficient quantity 

 for the treatment of a s ngle patient. [Illustration shown.] In the 

 Pasteur Institute, and in the British Institute of Preventive Medicine, 

 the antitoxic serum is apparently brought up to such a strength that 

 -j-^q- of a c.c. injected into a medium-sized guinea-pig (500 grammes, 

 or over 17 ounces) will protect it against an injection 24 hours 

 later of J c.c. of a culture of living diphtheria bacilli strong enough, 

 if given by itself, to kill the guinea-pig in 24 hours. It is usually 

 recommended that 20 c.c. of this serum should be given at the first 

 dose, and that if necessary a second 10 c.c. should be given half an 

 hour later. 



The method of testing the strength of the serum adopted by the 

 Germans is that devised by Ehrlich, who takes ten times the lethal 



