134 Twenty-Second Annual Report of the 



thereby results. The delivery of certified milk by the producer to 

 several points of distribution, if in different counties, often sub- 

 jects him to various regulations proportionate to the number of 

 counties to which his product goes, because the requirements in 

 one county may not be acceptable in another. The control 

 and certification of raw milk for the feeding of children should 

 be under the supervision of the highest possible authority, prefer- 

 ably the Federal Government. Where distribution of this 

 product is intrastate, this power is not vested in the National 

 Government, and, therefore, State authority should be supreme. 

 The present haphazard and complicated method should be super- 

 seded by a uniform system which would accept certification in 

 one State or portion of the State as satisfactory without regard to 

 the ultimate disposition of the product itself. At the present time 

 the practice of having this great food subject to so many conflict- 

 ing regulations and restrictions is unsatisfactory. 



Considerable difficulty is experienced in impressing upon own- 

 ers and veterinarians the necessity of considering animals dis- 

 eased after having once reacted to a tuberculin test. It is the 

 practice of many custodians as well as veterinarians to request, 

 and in many instances insist upon a retest of reactors with the ob- 

 ject of having same released if found to pass a second test. To one 

 not familiar with the irregular results found in retesting reacting 

 animals, there might seem to be no objection to this procedure. It 

 should be understood, however, that many individuals which are 

 tuberculous and have given indication of such condition as result 

 of test, will upon subsequent retest fail to react. Why this should 

 occur is not clearly established. It is probable, however, that it 

 is brought about by the immunizing effect of previous doses of 

 tuberculin, by intermittent susceptibility of the individual to the 

 action of tuberculin, by the disease having become arrested in its 

 development, or by other unknown conditions which may render 

 subsequent tests unreliable and therefore misleading and con- 

 fusing. 



It is evident, therefore, if the practice of ignoring reactors which 

 subsequently pass satisfactory test is followed, that herds in which 

 such animals are kept are frequently subjected to reinfection, due 

 to the fact that such individuals may and oftentimes do develop 

 active tuberculosis and become spreaders or distributors of the 



