APPENDIX. 495 



2 1 . Picric Acid, Solution of. 



Make a saturated solution in distilled water. 



22. Picric Acid, Kleinenberg's solution of. 



To a cold saturated solution of the acid add 2 parts of 

 nitric or concentrated sulphuric acid. 



Filter, and add to the filtrate three times its bulk of 

 water. 



Immersion of from 3 — 5 hours will suffice for most 

 preparations. 



23. Potash Solution.* 



Dissolve 5 grammes of potassic hydrate in 100 cubic 

 cent, of water. 



24. Sachs's Food-solution for green plants. 



Distilled water 1000 cub. cent. 



Potassium nitrate i gramme. 



Sodium chloride o'5 gramme. 



Calcium sulphate o'5 gramme. 



Magnesium sulphate 0*5 gramme. 



Calcium phosphate o"5 gramme. 



To this solution add a trace of a weak solution of ferric 

 chloride. The calcium phosphate is only slightly soluble 

 in water. 



25. Schulze's Macerating mixture. 



Dissolve I gramme of potassium chlorate in 50 cub. cent, 

 of nitric acid. Immerse the tissue in this solution, and 

 heat it. The tissue will then readily break up into its 

 constituent cells, their middle lamellae being dissolved. 



Cold maceration often gives better results, but takes 

 longer. 



Take care that the gases given off from the mixture do 

 not injure the microscope. 



26. Schulze's Solution. 



Dissolve some zinc in hydrochloric acid ; permit the 

 solution to evaporate, in contact with metallic zinc, until 

 it has attained a syrupy consistence. Saturate the syrup 



