Although we haven't tested this recipe ourselves (we're still trying to figure out where to get huckleberries), here's a version with modernized baking instructions if you'd like to give this cake a try. Although they have a somewhat different taste, blueberries would make a good substitute for huckleberries.
Marion Harland's Huckleberry Cake
1 cup of butter
2 cups of sugar
3 cups of flour
5 eggs, separated
1 cup of whole milk
1 teaspoon of baking soda, dissolved in water
1 teaspoon of nutmeg
1 teaspoon of cinnamon
1 quart of ripe, fresh huckleberries, thickly dredged in flour
Preheat the oven to 350 degrees. Separate the eggs. In a stand mixer, beat the egg whites until stiff peaks form. Gently spoon into another bowl if you don't have a second mixer bowl. Cream the butter and sugar until light and fluffy. Beat the egg yolks in a separate bowl and add to the butter and sugar, mixing until incorporated. Add the milk, flour and spices, and mix. Gently fold in the egg whites and baking soda. Add the huckleberries and gently stir. Pour into a loaf pan and bake until a cake tester (or skewer) comes out clean. You should start checking around the 30-minute mark.
From Common Sense in the Household by Marion Harland