John B. Nelson

Learn More
The spontaneous appearance of a second paratyphoid infection in a guinea pig population during the endemic stage of an earlier epidemic is reported. A comparative study of the gross pathology of the two infections indicated a difference in the loci of development of the respective organisms in the animal host. The two types were readily differentiated by(More)
The infective capacity of three bacteria commonly encountered during a study of natural middle ear disease in a rat colony has been determined by direct intra-aural injection in young rats. One week after the introduction of B. actinoides 75 per cent of the rats showed a purulent exudate in the injected middle ear cavity and 65 per cent yielded pure(More)
Whole, shaken and heated suspensions of two Salmonella species were compared as to agglutinability, absorptive capacity and antigenic properties. The results were in general agreement with the flagellar antigen concept of Smith and Reagh. The removal of flagella by shaking or heating (100 degrees C.) resulted in altered agglutinability manifested by failure(More)
A special colony of albino rats was built up by selection and isolation from a population in which middle ear disease was highly prevalent. No cases of aural infection occurred in the selected group, whereas its precursor showed a crude incidence of 57 per cent. The subjection of selected rats to a rachitic diet and to overcrowding did not predispose to the(More)
The introduction of vaccinia virus into the skin of swine calls forth a typical vesicular reaction which may be followed by a solid immunity. This acquired state of resistance was utilized in determining the route of immunity transmission from sow to young. The suckling young of immune sows, vaccinated on the 7th day or earlier, showed no reaction to the(More)
  • J B Nelson
  • 2003
A group of 105 breeders and 36 unweaned guinea pigs was tested to determine the extent of specific fecal excretion and the proportion of serum reactors in a population naturally infected with two types of B. paratyphi. The second, more recent type of organism was isolated from the feces of 3 breeders and 3 young. No carriers of the first type were detected.(More)
The salt-free water washings of a sensitized motile bacterium (B. aertrycke) were found to cause a floccular agglutination in the presence of both whole and deflagellated antigen. Evidence was presented that the water washings when salt-free contained flagella and flagellar agglutinin and that clumping occurred upon the addition of saline. The floccular(More)
  • J B Nelson
  • 2003
Three types of an uncomplicated fowl coryza, differing in the onset and duration of symptoms, developed after the intranasal injection into normal birds of exudate from natural cases. Protection tests were carried out with 2 of the types in an attempt to explain why the "bacillary" disease regularly ran a shorter course than the "exudate" disease.(More)