"Ger-panese" words

There are a lot of Japanese words that come from the German language. It is said that many of them are words related to medicine or chemistry.

アルバイト(a-ru-ba-i-to)
カルテ(ka-ru-te)
テーマ(te-e-ma)
アレルギー(a-re-ru-gi-i)
. . .

Now that is a long list of international words which have come via German into Japanese: medicine and chemistry rely heavily on words of Latin or Greek origin. As to the purely German words, I like Abendrot und Morgenrot the best, Rucksack and the other climbing-related ones spark my curiosity. When was it that Japan was fascinated by German-speaking mountaineers?

(I am pleased to see that you read my reports carefully and chose to answer a question hidden in there!)

Student mountaineers in Japan in old times used to study German at school. Besides, the introduction of the “Wandervogel” movement from Germany might have influenced the influx of German words related to moutaineering, albeit wandering and mountaineering are different.

Theoretically, I could now update my statistics here on LingQ: I know a lot more Japanese than I thought!