TRANSACTIONS OF SECTION B. 605 



The effect of heating a solution of diastase as above indicated is to weaken 

 its action and also to produce an alteration in the enzyme molecule, which is 

 moreover a permanent one, for the diastase retains its altered properties when 

 reprecipitated from its solution by alcohol and allowed to act on starch paste at 

 or below 55°. The alteration of the diastase is assumed by the production of 

 d-fflucose when it acts on starch paste, and it appears to commence when a 

 solution of the enzyme is heated below 60°; although, judging from the small 

 amount of (f-fflucose formed by its action, the change at the last-named tem- 

 perature is not complete. As the temperature of preheating the solution is increased, 

 the amount of d!-glucose it is capable of producing also increases, the maximum 

 amount being obtained by the action of diastase which has been preheated in 

 solution at 68° to 70° for fifteen to thirty minutes. Above this temperature the 

 destruction of the enzyme is so rapid that a much larger proportion of it has to be 

 employed to attain the stage of the reaction at which <Z- glucose appears. Still 

 d-glucose is formed by diastase which has been restricted at temperatures up to 

 78° and probably above this. It has been observed in all cases that when, after 

 the'maximum amount of rf-glucose has been formed, the solution is kept at the 

 temperature of hydrolysis, usually 5-5°, the sugar just mentioned diminishes in 

 amount, and the o"^ccurrence of this apparent condensing action of the enzyme may 

 probably explain the failure in several cases to detect (/-glucose among the products 

 of hydrolysis (compare the previous abstract). The maximum amount of </-glucose 

 formed in any case does not exceed about 12 per cent, of the total hydrolytic 

 products. 



6 The Chemical and Physical Characters of the so-called ' Mad-stone' 



By Dr. H. C. White. 



It is a widespread current superstition in the Southern States of America that 

 the sting of a venomous snake and the bite of a rabid animal (dog, &c.) may be 

 detected and discriminated from an innoxious wound, and the venom of the wound 

 extracted, by application of what is called the ' mad-stone.' Several of these stones 

 came opportunely into the hands of the author, and an examination of their 

 character was made. 



The ' mad-stone ' of current superstition is a very rare concretionary calculus 

 found in the gullet of the male deer. As extracted it resembles a water-worn 

 pebble, oblong in form, varying in size, but not greater, perhaps, than 3 inches in 

 length' by 1^ inch in thickness. A smooth flat surface is given to one side by 

 rasping. The examination was directed to the following points: — 



1. Chemical Composition.— Foundi to be chiefly tri-calcic phosphate. Exact 



figures of analyses given. • , , 



2. Adherence to Cut and Torn Flesh-wounds. — Found _ to _ vary with the 

 mechanical character of the wound and the mode of application of the stone, 

 without regard to venomous or non-venomous character of the wound. 



3. Absorbiijg Poiver. — Immersed in water the stones were found to absorb to an 

 extent of 5 per cent, of their weight. Applied to fresh wounds and carefully 

 adjusted, blood and other fluid absorbed to a maximum extent of 23 per cent, the 

 weight of the stone. 



4. Character of Matter absorbed.— The stone after application to the wound 

 is boiled with water, or milk (in accordance with the superstition). The fluid is 

 discoloured, and is shown to be toiic in the case of a known venomous wound. No 

 difference in discoloration is observable in venomous and non-venomous wounds. 

 That the stones are not curative is shown by the death of animals from venomous 

 ■wounds after application of the stone. 



The literature of the subject has been examined. The ' mad-stone ' super- 

 stition seems quite ancient. It was current in New England in Puritan times. 

 The author has in his possession an authenticated ' mad-stone ' dating from 1654. 

 This, however, is a moderately porous sandstone, entirely different from the 



