240 EXPERIMENTAL INVESTIGATION OF THE ACTION OF MI:DICINES. 



prevent fermentation. To test this, two glass-tubes or flasks 

 are filled with a mixture of milk- water, grape-sugar, and chalk 

 (from which carbonic acid will be set free by the lactic acid 

 formed), or with a solution of grape-sugar or yeast. To one of 

 them a certain amount of the substance to be tested is added, 

 and both are then inverted over mercury and kept in a warm 

 place for several days. The amount of gas developed is then 

 measured ; and, if the addition of the substance have hindered 

 the pi'od action of gas, we know that it has hindered fermenta- 

 tion in the same proportion. It has thus been found that 

 quinine, amounting to y^th part of the mixture, completely 

 stopped the development of vibriones or the production of gas ; 

 and other substances have a similar effect. 



As many cases of indigestion, acidity, flatulence, vomiting, 

 and summer diarrhoea, more especially in children fed by hand, 

 are most probably due to the fermentation of starchy and sac- 

 charine food caused by vibriones, Binz thinks that creasote, 

 quinine, &c., are serviceable in their treatment by stopping this. 

 As it is the local action that is wanted, the longer the medicine 

 remains in the intestine before being absorbed, so much the 

 better will its effect be ; and thus the greater benefit derived 

 from bark than quinine in some such cases might be explained. 



Action on Putrefaction. — The antiputrescent action of drugs is 

 tested by putting a square of boiled white of egg into each of 

 two vessels containing water and setting them in the sun. To 

 the liquid in one vessel the drug is added, and the rapidity with 

 which the edges of the square of white of egg on it become 

 decomposed and soft is noted and compared with that in the 

 other vessel. Instead of white of egg, a piece of meat or bread 

 may be used. The relative power of different drugs in stopping 

 putrefaction does not always correspond to the ideas which we 

 would be inclined to form ; for who would think that quinine 

 would be more powerful than such antiseptics as creasote, 

 chloride of lime, or arsenic ? and yet such is said to be the case. 

 So powerful is quinine, that a piece of meat placed in a solu- 

 tion of f per cent, of the sulphate, with a little dilute acid, 

 remained in summer without decomposition till the fluid was 

 dried up. 



