13f5 THE A3IERICAN MONTHLY [Api-il 



Natural and Acquired Immunity. 'I'lio natural ininuin- 

 ity of certain animals to certain diseases; even when the 

 actual virus is injected, has lonj^^ been known. Recently 

 careful investig-ations have been carried out at the Pas- 

 teur Institute at Lille. In the experiments use was made 

 of the following- poisons; an animal virus, serpent's venom, 

 and a veg-etable poison (abrine) ])re])are(l 1)V maceratini;: 

 jequirity seeds in water. They found that the immunity 

 of pigs and hedgehogs to venom and of fowls and tortoises 

 to abrine could not be due to the presence of antitoxins in 

 the blood previously to inoculation, for the serum of the 

 normal animals had no protective effect on susceptible 

 animals, nor had it any neutralizing effect on the poison 

 when mixed with it outside the body before inoculation, in 

 both these respects differing from serum containing anti- 

 toxins. The}^ were also unable to discover any antitoxic 

 substance in the brain, liver, spleen, or other org-ans of 

 the normal animals. They hold therefore, that the anti- 

 toxic serum is independent of immunity, since that may 

 exist when no antitoxic properties are possessed by the 

 serum. They attribute both kinds of immunity to special 

 characters of the cells of the body.- — Lancet. 



Bartonology Technique of Obtaining Serum and Dried 

 Blood. —Drs. Hermann Biggs and William H. Park give 

 the following methods for collecting blood to diagnose 

 typhoid fever by the Widal method. Blood may be easil}- 

 obtained by pricking the tip of the finger or the ear. Two 

 or three large drops should be collected on a glass slide and 

 allowed to dry. Paper is not as g-ood a receiver for the 

 blood as glass, for the blood soaks more or less into it, and 

 later, when it is dissolved, some of the paper fibre is apt to 

 be rubbed off with it. 



In ])reparing the sjiecimen for examination the dried 

 blood is l)i-uught into solution l»v mixin*^- it with ai)out live 

 times the (juantity of water. Then a drop of this decid- 

 edly reddish mixture is placed on a cover-glass and to it is 

 added a drop of fifteen-to-twenty-hour bouillon culture of 

 the typhoid bacillus. The two drops, after being mixed. 



