This paper contains the results of the Lange reaction on the spinal fluids of some sixty odd children and infants. We are reporting these because of the evidence that the colloidal gold reaction is of undoubted value as an aid in the early diagnosis of many cerebrospinal diseases occurring in such patients.
The first work on colloidal gold was that done by Michael Faraday1 in 1857. His colloidal solutions were made by reducing gold chlorid with phosphorus. It was not, however, until 1898 that Zsigmondy2 devised the present-day method for making clear solutions or suspensions of colloidal gold. He gives several methods for making these gold hydrosols. The first method is the one used in making the indicator for our tests. Briefly, a dilute solution of gold is mixed with potassium carbonate and reduced at the boiling-point by formaldehyd.3 If clear red solutions are desired, which can