THE SERUM TREATMENT OF DIPHTHERIA. 517 



The horses selected for the purpose of supplying serum should, 

 Roux states, be ordinary coach horses from six to nine years old, 

 well nourished but incapacitated for work on account of some in- 

 jury of the limbs. Such horses must be carefully examined to 

 determine the absence of lesions of the internal organs, especially 

 of the kidneys, while the absence of tuberculosis or glanders must 

 invariably bo determined by a failure of the animal to react to an 

 injection of tuberculin or mallein.* Roux reported the details of 

 the process in a horse seven years old, weighing four hundred 

 kilogrammes, that was injected beneath the skin of the neck or 

 behind the shoulder with toxine, one tenth of a cubic centimetre 

 of which sufficed to kill a guinea pig weighing five hundred 

 grammes in forty-eight hours. 



Day. Injected. 



1st J c. c. of toxine with ten per cent iodine. 



No local or general reaction. 



2cl, 4th, 6tb, 8th :^ c. c. Do. Do. 



13th, 14th. Ic.c. Do. Do. 



I7th ^ c. c. of pure toxine. Slight reaction. 



22d 1 c.c. " " " " 



23d 2 c. c. " " " " 



25th 3 c.c. " 



28th, 30th, 32d, 36th 5 c. c. " " 



39th, 41st 10 c. c. " " 



43d, 46th, 48th, 50th 30 c. c. of pure toxine. (Edema that dis- 

 appeared in twenty-four hours. 



53d, SVth, 63d, 65th, eYth 60 c. c. of pure toxine. 



'72d 90 c. c. " " 



80th 250 c. c. " " 



In two months and twenty days this horse received more 

 than eight hundred cubic centimetres, or twenty-five ounces, of 

 toxine with no worse symptoms than transient local swelling and 

 temporary rise of temperature about one degree centigrade. Se- 

 rum was obtained from this horse by bleeding it on the eighty- 

 seventh day, and immediately thereafter two hundred cubic cen- 

 timetres of toxine were injected into the vein with but moderate 

 subsequent fever. The latter procedure is less efficacious than 

 injecting smaller doses of toxine from time to time and allowing 

 the animal to rest for twenty days before being bled again. Roux 

 has horses from which blood has been taken more than twenty 

 times with a large trocar, yet the vein is as supple as in the be- 

 ginning. 



The serum obtained from the horse above referred to had a 

 preventive power above fifty thousand that is to say, a guinea 



* Tuberculin is a sterilized and filtered solution, in glycerin, of a culture of the tubercle 

 bacillus, and mallein a similar preparation of the glanders bacillus. 



