THE EARTHY AND ALKALINE PHOSPHATES. 349 



6. The time at which the alkalescence of the urine from fixed alkali generally 

 occurs, indicates the existence of some alkaline phosphate or of some carbonated 

 alkali in the food*. 



7. The result as regards diagnosis may be thus arranged : — 



Alkalescence of the urine from local causes. 1 Alkalescence from general causes. 



Blue paper made markedly red on drying. 

 Alkalescence constantly present. 



Always contains mucus in excess. 

 Prismatic crystals always to be found by 

 microscope. 



Blue litmus paper not made red on drying. 

 Alkalescence variable, usually soon after 



food. 

 Rarely contains mucus in excess. 

 When first passed generally contains only 



granular deposit. 



PLATE V. 



Fig. 1. Iridescent pellicles on some alkaline urine. 



Fig. 2. Amorphous deposit in alkaline urine. 



Deposit on boiling phosphate of soda with chloride of calcium, or with sul- 

 phate of magnesia. 



Fig. 3. Chloride of calcium with acid phosphate of soda, or with common phos- 

 phate of soda ; after long standing. 



Fig. 4. Phosphate of soda with little chloride of calcium. 

 Bone-earth phosphate. 



Fig. 5. On boiling phosphate of soda with sulphate of magnesia and little biphos- 

 phate of soda. 



Fig. 6. Phosphate of soda with sulphate of magnesia ; after long standing. 



Appendix. 



Later experiments have shown that the alkalescence from fixed alkali does not 

 depend on the nature of the food. For example, with a diet of animal food and di- 

 stilled water, the urine in four hours has been observed to be alkaline. Rather longer 

 after dinner it has also been found to be alkaline. Usually however, after a late 

 dinner, even if the water is secreted alkaline, it becomes mixed in the bladder during 

 sleep with acid water which is afterwards secreted and thus the alkalescence escapes 

 notice. 



It seems highly probable that the quantity of acid poured out into the stomach 

 sets free alkali sufficient in some cases to make the urine alkaline ; and from facts 

 which have been stated to me, it seems even possible that the same effect on the 

 water may sometimes be produced by the separation of acid by the skin. 



* See Appendix. 



