Now consider what it means for these people to have brought into their midst a number of competitors who can live even more cheaply than they can live, and who will consent to toil from morning to night for whatever they can get.

These new-comers are obviously able, in their eagerness for work, to drive down the rate of wages even below what represents starvation-point for the native worker.
The insistence of the poorer working-classes, under the stimulus of new- felt wants, the growing enlightenment of public opinion, have slowly and gradually won, even for the poorer workers in English cities, some small advance in material comfort, some slight expansion in the meaning of the term "necessaries of life." Turn a few shiploads of Polish Jews upon any of these districts, and they will and must in the struggle for life destroy the whole of this.

Remember it is not merely the struggle of too many workers competing on equal terms for an insufficient quantity of work.

That is terrible enough.

But when the struggle is between those accustomed to a higher, and those accustomed to a lower, standard of life, the latter can obviously oust the former, and take their work.
Just as a base currency drives out of circulation a pure currency, so does a lower standard of comfort drive out a higher one.