The proportionate expense of the joint establishment and maintenance of a district welfare-house shall, as provided in this chapter, be apportioned among the several counties according to their population, excepting therefrom the population of municipalities which, as authorized in section 44:1-61 of this title, have elected not to participate, and the necessary sums required to be levied, assessed and collected shall be so raised by the board of chosen freeholders against the municipalities chargeable as provided in this chapter.
N.J.S. § 44:1-48