The isolation of veratric acid and protocatechuic acid from cockroach oothecae is described. Veratric acid was isolated by extracting the oothecae with potassium cyanide and sulfur dioxide, followed by several extraction steps and purification. The isolated acid was recrystallized and confirmed by melting point and elemental analysis. It was identified as veratric acid, with a melting point matching that of the authentic compound. The acid was further converted to its anilide, which also matched the authentic compound. Protocatechuic acid was isolated by a similar procedure and confirmed by melting point and elemental analysis. The phenolic substance in cockroach oothecae was identified as protocatechuic acid. The spectrophotometric determination of tyrosine and tryptophan in proteins is discussed. The absorption spectra of these amino acids in 0.1N NaOH were determined, and their curves were found to intersect at 257.15 and 294.4 mμ. Using these points, mixtures of tyrosine and tryptophan can be analyzed with high accuracy, provided the molar ratios are not greater than 20:1. The method involves measuring the absorption at these wavelengths and using the intersection points to calculate the concentrations. The Beckman photoelectric spectrophotometer was used for accurate measurements. The method was tested on various protein solutions, and the results showed that the technique is accurate and reliable. The method allows for the determination of tyrosine and tryptophan in small protein samples with minimal irrelevant absorption. The results were compared with other methods and found to be consistent. The method is suitable for analyzing proteins with a wide range of concentrations. The study concludes that the spectrophotometric method is effective for determining tyrosine and tryptophan in proteins.The isolation of veratric acid and protocatechuic acid from cockroach oothecae is described. Veratric acid was isolated by extracting the oothecae with potassium cyanide and sulfur dioxide, followed by several extraction steps and purification. The isolated acid was recrystallized and confirmed by melting point and elemental analysis. It was identified as veratric acid, with a melting point matching that of the authentic compound. The acid was further converted to its anilide, which also matched the authentic compound. Protocatechuic acid was isolated by a similar procedure and confirmed by melting point and elemental analysis. The phenolic substance in cockroach oothecae was identified as protocatechuic acid. The spectrophotometric determination of tyrosine and tryptophan in proteins is discussed. The absorption spectra of these amino acids in 0.1N NaOH were determined, and their curves were found to intersect at 257.15 and 294.4 mμ. Using these points, mixtures of tyrosine and tryptophan can be analyzed with high accuracy, provided the molar ratios are not greater than 20:1. The method involves measuring the absorption at these wavelengths and using the intersection points to calculate the concentrations. The Beckman photoelectric spectrophotometer was used for accurate measurements. The method was tested on various protein solutions, and the results showed that the technique is accurate and reliable. The method allows for the determination of tyrosine and tryptophan in small protein samples with minimal irrelevant absorption. The results were compared with other methods and found to be consistent. The method is suitable for analyzing proteins with a wide range of concentrations. The study concludes that the spectrophotometric method is effective for determining tyrosine and tryptophan in proteins.