franchises was rejected, partly in consideration of
the principle of national supremacy, and partly on the ground that the
corporate franchises were private property. This case also qualified
Pollock _v._ Farmers Loan and Trust Company to the extent of allowing
interest on State bonds to be included in measuring the tax on the
corporation. Subsequent cases have sustained an estate tax on the net
estate of a decedent, including State bonds;[234] excise taxes on the
transportation of merchandise in performance of a contract to sell and
deliver it to a county;[235] on the importation of scientific apparatus
by a State university;[236] on admissions to athletic contests sponsored
by a State institution, the net proceeds of which were used to further
its educational program;[237] and on admissions to recreational
facilities operated on a nonprofit basis by a municipal
corporation.[238] Income derived by independent engineering contractors
from the performance of State functions;[239] the compensation of
trustees appointed to manage a street railway taken over and operated by
a State;[240] profits derived from the sale of State bonds;[241] or from
oil produced by lessees of State lands;[242] have all been held to be
subject to federal taxation despite a possible economic burden on the
State.

IS ANY IMMUNITY LEFT THE STATES?

Although there have been sharp differences of opinion among members of
the Supreme Court in recent cases dealing with the tax immunity of State
functions and instrumentalities, it has been stated that "all agree that
not all of the former immunity is gone."[243] Twice the Court has made
an effort to express its new point of view in a statement of general
principles by which the right to such immunity shall be determined.
However, the failure to muster a majority in concurrence with any single
opinion in the more recent of these cases leaves the question very much
in doubt. In Helvering _v._ Gerhardt,[244] where, without overruling
Collector _v._ Day, it narrowed the immunity of salaries of State
officers and federal income taxation, the Court announced "* * *, two
guiding principles of limitation for holding the tax immunity of State
instrumentalities to its proper function. The one, dependent upon the
nature of the function being performed by the State or in its behalf,
excludes from the immunity activities thought not to be essential to the
preservation of State governments even though the tax be c