The article describes a working and scientific path as well as public activities of the graduate of the Faculty of Medicine of the University of Yuryev (Tartu), Professor of the Second Petrograd University and the University of Latvia, Honorary Doctor of the University of Latvia, the holder of the Order of Three Stars, III and IV Class, the Legion of Honour (France) and the Cross of Recognition, II Class during the period of 50 years of his professional life. Professor is the author of 180 scientific papers, including five books, on research of chemical composition of food products and is the founder of the science of food products in Latvia. In Petrograd for the period of ten years (1908 – 1918) he worked in the Ministry of Agriculture of Russia as Vice-Director of the Bacteriological Laboratory and the Head of the Chemical Department. He studied chemical composition of food products, in particular honey, milk, common salt in different regions of Russia. Professor Zarins worked at the problem of producing condensed milk to be used at front during the war. He went on academic trips to Germany, Holland, Sweden, developed the methods of wine production, and made portable testing units for apiaries intended for detection of adulterated honey and beewax. In Petersburg he took an active part in the work of the Russian Red Cross and the Committee of Refugees from Latvia. By order of the Government he guided drafting of the Law on Food Products. Upon return to his homeland in 1919 he took an active part in foundation of the University of Latvia and became the only representative of teaching stuff, who participated in organisation of three faculties – Faculty of Medicine, Veterinary Medicine and Chemistry. Professor Zarins was a member of the Reorganisation Commission of the Polytechnical Institute, an Acting Dean of the Faculty of Medicine, a member of Organisation Commission (Council) of the University of Latvia, as well as a member of commissions on drafting the Constitution of the University of Latvia. He took an active part in organisation of the Pharmaceutical Division of the Faculty of Chemistry and was one of the founders of pharmaceutical education in Latvia. For 13 years (from 1922 to 1944) he was elected as the Dean of the Faculty of Chemistry. He was a member of the Prudential Committee of the University of Latvia, a member of Deans’ Council, a representative of the Faculty of Chemistry in the University Council. During his professional career he was a scientific supervisor of 39 theses. At the same time he continued his scientific work in research of chemical composition of milk, butter, cheese, fats, bread, meat, tinned food, as well as mineral water, wine, beer, and other alcoholic drinks and their “quality factors”. He also continued public activities in more than ten societies and organisations in Latvia, France, Italy, Germany and other countries. From 1931 to 1940 he was the Chairman of the Board of A/S “Farmācija”, from 1932 to 1936 he was the Chairman of the Chemical Society of Latvia. Professor Zarins is a co-author of the Law on Pharmacology, the Law on Wines, and the Law on Food Products. For his distinguished services to the Latvian Red Cross he was awarded the Cross of Honour, I Class and the International Cross of Honour of the Belgian Red Cross. He bequeathed his estate “Šautuves” to the University of Latvia and became one of the Gold Maecenas of the University of Latvia.