In this work, the subject of Nicolaus Ostoich's book On the Influence of Light on the Human Organism is systematically treated. The author's work is important for Croatian and world culture because of several components that are intertwined in it: heliotherapy as a topic of alternative medicine, the fact that it was written by a Croatian author in the first half of the nineteenth century, and the linguistic-pedagogical-didactic dimension that the book contains. Speaking about health in Latin is the famous thought mens sana in corpore sano. The development of medicine has left many works written in Latin in the history. The work in question talks about treatment using the sun's rays, that is, about heliotherapy. Works have also been written about other methods that today we know to put in the category of alternative medicine; in addition to the mentioned heliotherapy, we have homeopathy, macrobiotics. Aside from the main theme of the book, the fact is that the work was written in 1835 during the period in Croatian history known as the Croatian National Revival. The essentially most important event would be the declaration of the Croatian language as official, while Latin was used among the elite as a secondary shield against Germanization and Hungarianization. Apart from the relevant officialdom, many works in Croatian literature, either scientific or artistic, were written in Latin. And the last thing that is worth pointing out is about language matters and upbringing and education. Croatian has many Latinisms, which is why it can be pointed out that Latin is in everyday use, and it is worth pointing out the popularity of learning Romance languages, especially Italian, French and Spanish. The importance of learning Latin by connecting it with other languages are features that an individual can highlight: cultural connection with other peoples, tendency to learn foreign languages and mutual respect in general. One language and one topic connect people, cultures, but they can certainly open up new interests, longings, plans and so on.