20 Dr John Davy on the Slaking of Quicklime. 



firmly by a cord. After about fifteen minutes an explosion 

 took place. The report was like that of a pistol. The jar 

 was broken into several pieces, and some of them were pro- 

 jected many yards from the spot. 



Now, as coal is not nearly so resisting as sandstone, 

 and as its boring is easily effected, I venture to express the 

 hope that the experiment may be repeated in a colliery. 

 It is easily made, at a cost not worth mentioning, is at- 

 tended with no serious danger ; and should it be successful, 

 it may conduce to the saving of many valuable lives. 



Some Observations on the Blood, chiefly in relation to the 

 question, Is Ammonia in its volatile state one of its Normal 

 Constituents^ By John Davy, M.D., F.E.S. Lond. and 

 Edin., &c. 



Of the many questions which have been propounded 

 respecting the blood, there are two in particular which of 

 late years have excited some interest and have given rise 

 to much discussion ; one, whether it contains any ammonia 

 in a volatile state ; — the other, whether the escape of volatile 

 ammonia is the cause of that characteristic quality of healthy 

 blood, its coagulation ? 



The latter question has been answered, as is well known, 

 in the affirmative by Dr Benjamin Eichardson in a work of 

 much ability, a successful prize essay, which w^as published 

 in 1858. Shortly after, viz., in the following year, I 

 endeavoured to show that this is not the case. The experi- 

 ments I made were mostly on the blood of the common fowl, 

 which I selected chiefly on account of the rapid manner in 

 which the blood of birds coagulates, and its high tempera- 

 ture during the time the phenomenon is in progress. The 

 results were all negative. The coagulation took place 

 without obvious difference of time whether the blood was 

 allowed to coagulate in a closed vessel, or exposed to the air, 

 as, for instance, when received into a vial, the blood com- 

 pletely filling it, and instantly closed by a glass stopper, — 

 or into a vial of the same kind and the stopper left out. 

 Further, I found that when ammonia in a notable quantity 



