Coloroscopic investigations

Summary

The above mentioned tests were chosen as examples for the following reasons:

• 1. As commonly employed the Limit of Identification and the Limit of Sensitivity are very satisfactory.

• 2. The tests are moderately specific.

• 3. They require few manipulations.

• 4. The control where possible was practically colourless.

We found the tests to be speedy and infallible — if the directions given above are closely followed, interfering ions being absent. While daylight illumination for the microscope is not essential, it certainly is preferable, as several of the well-known magnesium tests (p-nitrobenzene azo-a-naphthol, or Titan yellow) were quite satisfactory in daylight, but unreliable with artificial illumination.

It will be understood that we do not consider this method in general to be superior to Tüpfelanalyse for very obvious reasons, but we feel it might have practical uses in microbiochemistry and microgeology. There is in preparation a further paper on the quantitative aspects of micro-coloroscopy.

In conclusion we wish to acknowledge our indebtedness to ProfessorFriedrich Emich of Graz and to ProfessorFritz Feigl of Vienna, not only for practical details and general information but also for their kindly interest in this Institute.