APPENDIX 279 



tion, a representative sample of each batch, consisting of 

 at least 15 cubic centimeters of the mixture, shall be 

 taken by a bureau employee. This sample shall be known 

 as the "Virus-test sample. " 



Paragraph 3. Simultaneous virus which has been 

 mixed as provided in this section, after withdrawal of 

 the "Virus-test sample," shall have added to it a suffi- 

 cient quantity of a 5 per cent solution of phenol so that 

 the virus will contain one-half of 1 per cent phenol by 

 volume. This phenolization must be accomplished with 

 accuracy and in a manner which will prevent undesir- 

 able changes in the product. After thorough mixing in a 

 single container, a representative sample, consisting of 

 at least 100 cubic centimeters, collected in three contain- 

 ers, shall be taken by a bureau employee. This sample 

 shall be known as the "Virus-stock sample. " 



Paragraph 4. Simultaneous virus which has been 

 mixed and phenolized, as provided in this section, to- 

 gether with the virus-stock sample and the unused resi- 

 due of the virus-test sample, shall be placed under bu- 

 reau lock and held as provided under (&), section 1 of 

 Regulation 7 until such time as the tests have shown 

 the batch of virus to be virulent and free from contami- 

 nation. 



Paragraph 5. At least one container of the virus-stock 

 sample shall be held unopened under bureau lock, in the 

 manner provided in Regulation 7, for at least three 

 months after the expiration of the latest return date 

 shown upon the trade labels affixed to the immediate or 

 true containers of the product corresponding to the 

 virus-stock sample. Unless the virus is heated as pro- 

 vided in paragraph 6, section 3, of this regulation the 

 virus-test sample described in paragraph 2 of this sec- 

 tion shall be used to determine the freedom from con- 

 tamination of each batch of simultaneous virus. 



Paragraph 6. Two healthy calves, with mouths free 



