304 



Journal of Applied Microscopy. 



NUTRIENT BROTH. 



3. Filter infusion through cloth 



to remove meat. 



4. Titrate and record reaction of 



filtrate. 

 Say reaction r2.2 per cent. 



5., Weigh infusion. 

 Say 1800 grams. 



6. Set infusion on water bath, 

 keeping temperature below 

 6o°C. 



Ditto. 



Ditto. 



7. Add peptone, i percent. 18 gr. Ditto, and sheet gelatin Add peptone, 2 per cent. 18 gr. 



Add salt, 0.5 per cent. 9 gr. 10 per cent. 180 gr. Add salt, i per cent. 9 gr. 



S. After ingredients are dissolved, • Ditto. Ditto. 



titrate; reaction probably reaction probably 4.010 reaction probably -4.5 to +4.7. 



2.3 to ^2.5. r5.0. 



9. Neutralize (Fuller's method). 



Ditto. 



Ditto. 



To the 900 grams of meat infusion 

 (containing now peptone and 

 salt also) add 900 grams of the 

 3 per cent, agar jelly described 

 at head of this column. Since 

 agar is neutral, the reaction is 

 unchanged. 



10. Heat over boiling water (or steam) bath thirty minutes. 



11. Restore weight lost by evaporation to original weight of filtered meat infusion, i. e., that on 



which the per centage of peptone, salt, etc., were calculated — 1800 grams in eacJi case. 



12. Titrate — reaction probably +0.3 to +0.5. 



13. Adjust reaction to final point desired — generally to 1.5 per cent. 



14. Boil five minutes over free flame, ^\•ith stirring. 



15. Add water, if necessary, to make up loss from evaporation to 1800 grams. 



16. Filter through absorbent cotton, passing the filtrate through the filter repeatedly until clear. 



17. Titrate to determine whether or not the desired reaction has been maintained. 



18. Tube and sterilize. 



HiBBERT WiNSLOW HiLL. 



Director, Laboratory of the Boston Board of Health. 



A Black Finish for Table Tops. — Professor J. R. Slonaker gives a 

 formula taken from the Botan'u-al Gazette of 1897, last half, which he has used 

 for finishing laboratory tables : 



Sohition A, 07 g. sodium chlorate. 



(i7 g. copper chloride. 



1 1. water. 



Solution B, l.lO g. anilin chlorate. 



1 1. water. 



Paint the wood with solution k, allow it to just dry, follow with sohition B, 

 and allow it to dry in. If a dense black is desired three applications will be 

 necessary. After drying, the surface may be finished with oil as ordinary wood. 



