1. É feita uma revisão do método de KJELDAHL até 1950. 2. É dada a descrição de um método, trabalhando com amostras de material biológico contendo 0,14 a 0,70 mg de N. O desvio padrão encontrado foi de 0,0007 mg.
1. The determination of organic nitrogen by the KJELDAHL method is reviewed up to 1950. 2. A method is described in which samples of biological material containing from 0.14 to 0.70 mg. N were employed. The accuracy of the obtained results was evaluated and their standard deviation was found to be 0.0007 mg. Research is beeing carried out on kjeldahlization curves of different materials which is the object of a further paper

Material contrasts which were dependent on the doping were seen on integrated circuits during examination with the photoemission electron microscope (PEEM). Surface studies using the PEEM, Auger electron spectroscopy (AES), and secondary ion mass spectroscopy (SIMS) showed that these material contrasts can be traced to doping dependent coverage of the silicon surface by hydrocarbons.

The silica structure of the grass Panicum maximum were studied by electron and phase contrast microscopy. Several interesting kinds of silica formation (spiklets) were found. The most ineresting structures ressembels the "Schaumstruktur" found by HELMCKE in diatoms. Another interesting structure was described in the "silica cells" and a detailed study of the mophology of some different kinds of spiklets was made

Materialunterschiede, die von der Dotierung abhängig sind, werden an integriertenSi‐Stromkreisen durch Oberflächenuntersuchungen mit dem Elektronenmikroskop,durch Auger‐Spektroskopie und Sekundärionen‐Massenspektroskopie festgestellt.l Dabei handelt es sich um Verunreinigungen durch Kohlenwasserstoffe.