I owl Typhoid 'and Fowl Cholera 
69 
Kolmer brings out the following ways in which bacteria or their products 
might be treated in order to be used for immunizing purposes: 
1. The living organism may be inoculated. 
inoculation with a modified virus, or with 
ated or modified according to various methods. 
microorganisms attenu- 
a. By passing through a lower animal. 
b. By exposing microorganisms to air and light. 
c. By exposing microorganisms to heat. 
d. By dessicating or drying virus. 
to a high temperature for varying 
e. By exposing microorganisms 
lengths of time. 
f. By exposing microorganisms or their products to certain chemicals. 
3. By inoculating the bacterial constituents, as soluble toxins, bacterial 
extracts and products of bacterial extracts. eacieriai 
Bushnell and Patton (2) recognize three conditions in relation to the 
struggle between the host and invading parasite: 
1 ; In ^/kich the host possesses sufficient immunity to rapidly localize and 
destroy the invading organism. localize ana 
2. In which the invasion powers of the organism and the reactive powers 
and^eX^ro^ic 6 " eaUaUZe<3 ’ “ d the infeCtion beCOmes “><=**“<> 
3. An entire lack of ability of the host to localize and destroy the invading 
organisms. J s 
. three of the above conditions were encountered both in the field and 
m the artificial infection studies on avian typhoid. 
The production of antibodies is the basis for prophylactic vaccination 
(higure 29.) When antigenic substances, which probably are colloids of a 
protein nature, are introduced into the body, the antibodies are usually 
iighly specific for the antigen injected, but also may act as a general stimu¬ 
lant, and may induce the body cells to cast off small amounts of the antibody 
unrelated to the nonspecific agent injected. For disease diagnosis, birds are 
received at this station in all stages of paralysis. It has been a routine pro¬ 
cedure to vaccinate such birds with stock vaccine for avian typhoid and in 
some instances noteworthy results have been obtained, a small per cent of 
such birds responding quickly to this vaccination, and regaining normal 
coordination of body parts, the results possibly being due to body stimula¬ 
tion produced by the vaccine. It is also worthy to note that attempts to 
leproduce paralysis were not successful though inoculations were made with 
the Berkfield filtrate of emulsions of the brain, spinal cord, and various 
internal organs. 
In vaccination in the field against fowl typhoid, vaccines prepared by 
heating cultures as described by Kolmer in 2c. were used. The objective 
was the production of artificially acquired immunity for as great a length of 
time as possible. Autogenous vaccines were used as often as practicable in 
order that the specific organism might retain such natural potencies, as near 
as possible, as were maintained in the original organism. The rapid loss of 
virulence in stock cultures of E. sanguinaria gives rise to the belief that the 
natural potencies of the organism are changed by adverse conditions and by 
artificial life. Variants are also possible among the specie which might 
delay the processes of immunization if stock vaccines were used, and from 
field observations it was apparent that the mortality was checked with 
greater rapidity where the autogenous vaccine was employed. 
The use of heated suspensions proved the most practical method of making 
avian typhoid vaccines, and the most economical method of meeting the 
