Here's the text from page 19
For free, giving us this ship.
日本人。。。 ヤサシイネ ホント シンセツネ。。。 マズシイ国ニ。。。 ワタ
Japanese people... really are kind and gentle... to poor countries... I cry... thinking about it.
What's interesting in this panel is that the village elder had specifically referred to himself as the island's prime minister, and Dracula had also said that he'd make "the prime minister" bow before him. So, the joke is that Dracula has (kind of) succeeded in his pledge in this panel, but Tezuka doesn't actually come right out and say that.
People!! Japan gave us this ship!!
As evidence of our heartfelt gratitude... here...
Little girl... A flower wreath... here...
Our county's sole product. We'll give you as much as you want.