133 REPORT — 1873. 



lia^iiig' awakened the exhausted interest of physiologists in tlie subject), his special 

 object being to repeat the niuch-discussed tuvnip-cheese experiment. 



Every one knows what Dr. Bastian's observation is. It is simply this, viz. that 

 if a glass flask is charged witli a slightly alkaline infusion of turnip of sp. gr. 1015, 

 to which a trace of cheese has been added, and is then subjected to ebullition for 

 ten minutes and closed hermetically while boiling, and finally kept at fermentation 

 temperature, Bacteria develop in it" in the course of a few days. This experiment 

 has been repeated by Iluizinga Avith great care, and the accuracy of Dr. Bastian's 

 statement of fact confirmed by him in every particular ; yet, notwithstanding this, 

 he thinks that the evidence aflbrded by the"se results in support of the doctrine so 

 inadequate, that be, desiring to find such evidence, has thought it necessary to 

 repeat the observation under what he regards as conditions of greater exactitude. 



Huizinga's objections to Bastian's experiment are two. First, that when a flask 

 is boiled and closed hermetically in ebullition, its contents are almost entirely 

 deprived of air ; and, secondly, that cheese is a substance of mixed and uncertain 

 composition. To obviate the "first of these objections he closes his flasks, after ten 

 minutes' boiling, not by hermetically seahug them, but by placing over the mouth 

 of each, while in ebullition, a porous porcelain plate which has first been removed 

 from the flame of a Bunsen's lamp. The hot porcelain plate is made to adhere to 

 the edge or lip of the flask by a layer of asphalt, with which the edge has been 

 previously covered. The purpose of this arrangement is to allow air to enter the 

 flask at the same time that all germinal matter is excluded. It is not necessary to 

 discuss whether this is so or not. 



To obviate the second objection he alters the composition of the liquid used ; 

 he substitutes for cheese, peptone ; and for turnip-infusion, a mixture of the fol- 

 lowing composition in 1000 parts :— 



Grape-sugar 25 grammes. 



Potassium nitrate 2 „ 



Magnesium sulphate .... 2 „ 



Calcium phosphate 0-4 gramme. 



The phosphate is prepared by precipitating a solution of calcium chloride with 

 ordinary sodium phosphate, taking care that tlie chloride is in excess. The preci- 

 pitate of neutral phosphate so obtained is washed and then added to the saline 

 solution in the proportion given. On boiling it is converted into soluble acid 

 phosphate and insoluble basic salt, of which the latter is removed by infiltration ; 

 consequently the proportion of phosphate in solution is less than that above indi- 

 cated. To the filtrate, peptone is added in the proportion of 0-4 per cent. 



The peptone is obtained by digesting egg-albumen at the temperature of the 

 body in artificial gastric juice, made by adding the proper quantity of glycerine 

 extract of pepsin to water acididated with hydrochloric acid. The liquid so ob- 

 tained is first rendered alkaline by the addition of liquor sodfe, then slightly 

 acidulated with acetic acid and boiled. The syntonin thus precipitated is sepa- 

 rated by infiltration from the clear liquid, which is then evaporated to a sirup and 

 pouredin a thin stream into strong alcohol with constant agitation. The preci- 

 pitated peptone is separated after some hours and washed with alcohol, and re- 

 dissolved in a small quantity of water. The solution is again precipitated by 

 pouring it into alcohol in the same way as before, and the precipitate washed and 

 dried. 



Flasks having been half filled with the liquid thus prepared (in 1000, two each 

 of nitre and Epsom salts, a trace of phosphate of lime, twenty-five parts of grape- 

 sugar, and four parts of peptone), each is boiled for ten minutes, closed while boil- 

 ing with the earthenware plate as above described, and placed as soon as it is cool 

 in the warm chamber at 30° 0. The experiment so made gave, without any 

 exception, a positi^-e result in every case. After two or three days the fluid was 

 crowded with actively moving JBaderhnn termo. 



In June last I published in ' Nature ' a repetition of Dr. Bastian's experiments, 

 with a variation not of the liquid, but of the mode of heating. Instead of boiling 

 the flasks for ten minutes over the open flame and closin^' them in ebullition, I 

 boiled them, closed them hennetically, and then placed tliera in a digester, in 



