158 PRINCIPLES AND PRACTICE OF MILK HYGIENE 
A thick cord-like induration, about the thickness of a lead 
pencil, extending vertically through the middle of the teat, is a 
symptom of catarrhal mastitis; also nodular indurations in the 
walls of the teat canal and milk cistern. Only slight alterations 
may be present in the milk, or none at all. 
Atrophy is usually a symptom of an existing or previously 
existing catarrhal mastitis. Milk from the affected quarter 
may contain the organism responsible for the condition even 
when it shows no perceptible changes. 
(For the changes in milk occurring during udder disease 
see pages 105-110.) 
Firm, nodular swellings, not hot or painful, situated in the 
superficial parts of the udder tissue, which are not movable and 
which can be reduced by strong pressure, are retention cysts, 
formed by the blocking of the milk ducts. 
(b) SPECIAL EXAMINATION 
The character of the special examination will depend 
upon the information obtained during the general 
examination. 
If fever is suspected the temperature should be taken 
with a thermometer and an examination made for the 
other symptoms of fever (chill; irregularity of the sur- 
face temperature, especially of the extremities; accelera- 
ation of the pulse and respiration, loss of appetite, depres- 
sion, albuminuria). In cattle the increase in temperature 
as shown by the thermometer does not always correspond 
to the degree of fever indicated by the other symptoms. 
When thoracic disease is suspected the chest wall 
should be percussed. Areas of hepatization and solidifi- 
cation may thus be discovered. The area of the lungs 
of cattle which can be percussed is limited, however, and 
unfortunately tubercular solidifications usually occur 
below this area. Percussion may reveal painful condi- 
tions of the lungs and pleura and may also produce 
cough. 
