NATURAL IMMUNITY 53 



into chimpanzees, in which primary and secondary lesions develop, 

 corresponding mildly to human syphilis. Primary lesions can be 

 produced in lower monkeys. It can be transferred by intratesticular 

 inoculations to rabbits. 



Gonococcus infection occurs spontaneously in man only. No 

 typical lesions can be produced in experimentally inoculated ani- 

 mals, though death can be caused by large doses, probably by toxic 

 action. 



Influenza bacillus spontaneously infects man only. Experi- 

 mental infection is partly successful in monkeys only. (Pfeiffer 

 and Beck, Deut. med. Woch., 1893.) 



Glanders. Spontaneous infection occurs in horses and mules; 

 less frequently in sheep, goats, and camels. This disease, like plague, 

 may be regarded as primarily a disease of animals, but man may be 

 infected by direct or indirect contact with the diseased animal. All 

 domestic animals may be infected experimentally with ease, except 

 cattle and rats, in which cases large doses are necessary. Birds show 

 local reactions only. (Wladimiroff in "Kolle und Wassermann 

 Handbuch," Vol. 5, 2d Ed.) 



Plague occurs spontaneously chiefly in man and in rats. It has 

 also been found in California ground squirrels and in hogs during 

 plague epidemics in Hong Kong. It is highly infectious for guinea 

 pigs and white rats slightly less so for mice ; rabbits are much less 

 susceptible than guinea pigs. Dogs, cats, and cattle are relatively 

 resistant. Birds appear to be immune. Cold-blooded animals are 

 immune unless artificially warmed. (See above.) 



Malta fever occurs spontaneously in man and in goats. It is 

 pathogenic for all mammals, but it is not fatal for lower animals 

 when the organisms are directly cultivated out of the human body. 



Diphtheria occurs spontaneously in man only. Experimental in- 

 oculation is fatal in guinea pigs, rabbits, dogs, cats, and birds. Eats 

 and mice are highly resistant. The typical pseudomembranous in- 

 flammation can be produced in susceptible animals only after pre- 

 vious injury of the mucous membrane, and then it rarely shows any 

 tendency to spread. 



Tetanus is spontaneous in man, horses, cattle, and sheep. It is- 

 found rarely in dogs and goats. Birds are highly resistant to ex- 

 perimental inoculation. 



Anthrax is primarily a spontaneous infection of cattle, sheep, 

 and horses ; it occurs in man largely through direct or indirect contact 

 with these animals. Guinea pigs, rabbits, and white mice are very 

 susceptible to experimental inoculation. Rats and hogs are less sus- 

 ceptible, and dogs are relatively resistant, though they can be regu- 

 larly killed by moderate doses intravenously injected. Birds and 

 cold-blooded animals are highly resistant. 



Asiatic cholera develops spontaneously in man only. Rabbits 



