f 
110 REPORTS ON THE STATE OF SCIENCE.—1918. 
Formaldehyde is unaffected by colloidal palladium, but in the 
presence of methylene blue, nitrates, indigo, or other easily reduci- 
ble bodies, the aldehyde is oxidised, and the reducible bodies act as 
. “receivers” for the hydrogen. ‘ 
Bach, Arch. Sci. phys., Généeve, 32, 27-41 (1911), assumes the 
existence of a perhydride of oxygen in the water, H,O, analogous 
to peroxides in the peroxidase reaction. Such a compound has 
never been isolated, and one feels that its assumption is not required, 
since the theory of the activation of the water by the enzyme amply 
meets the case. 
An enormous mass of work has been done on the Schardinger 
reaction, but a recent paper by Lee and Mellon (J. Ind. Eng. Chem. 9, 
360 (1917) ) ably summarises the present position. The conclusions 
reached are :— 
(A) Methylene blue as it occurs in Schardinger’s reagent F.M.B. 
is not decolourised by :— 
(i) Normal fresh milk in less than 20 minutes. When 
decolouration was effected in 10 mins. or less, the 
milk was found to contain 1,000,000 or more micro- 
organisms per lec. 
Gi) Milk pasteurised at 70° C. for 10 mins., unless 
approx. 48 hours have elapsed since the milk was 
pasteurised, or until the bacteria have had time to 
multiply sufficiently. 
Gii) Old milk in which formaldehyde had inhibited 
the growth of bacteria. 
(B) Schardinger’s reagent, F.M.B., is as a rule decolourised by 
normal milk allowed to “age” under ordinary conditions 
of temperature for 24 to 48 hours. 
(C) Pasteurisation increases the time required for the de- 
colourisation of the reagent. 
(D) In general, no proportionality exists between the time 
required for the decolourisation of the reagent and the 
number of bacteria in milk. In a given sample, how- 
ever, a general relation seems to exist between the two 
‘up to a given point of acidity. 
(EK) Inasmuch as there is no absolute parallelism between. the 
number of bacteria in the milk and the ¢ime required to 
decolourise the reagent, but that the relationship seems to 
exist in a given sample of milk, it would indicate that 
‘ reductase is of bacterial action, but that not all bacteria 
found in milk produce this enzyme. 
(F) It seems probable that formaldehyde either gradually retards 
the action of the reductase or destroys it. 
Several very interesting observations on the Schardinger reaction 
have been made by various investigators. Thus :— 
Utz (Zeit. 7. angew. Chemie (16), 871 (1903) ) showed that sour . 
milk could be made to give the reaction by adding to it 
NaOH or other alkalies. 
Rullmann (Biochem. Zeit. (32), 446 (1911) ) showed that instead 
of HCOH one could use formic acid for the F.M.B% test. 
