Abstract: A liquid-cooled, four-valve cylinder head for a multi-cylinder internal-combustion engine comprises a casting having a cooling-fluid space between the cylinder-head bottom and a cylinder-head cover in which supporting struts are arranged for reinforcing the cylinder-head bottom, valve channels of gas-reversing valves and chambers for receiving secondary combustion spaces. Above the cooling-fluid space is located a control space with guide housings for receiving the cup tappets for the actuation of the gas-reversing valves. In order to obtain a cylinder-head construction which is structurally rigid and nevertheless can easily be produced, the chambers are cast together with the valve channels within the cooling-fluid space. Further, the supporting struts are equipped with ribs projecting into adjacent combustion-space portions, and the lateral outer walls of the cylinder-head housing are connected to one another in the region of the control space by transverse booms.

Abstract: New reactive asymmetrical dicarboxylic acid ester compounds of the formula ##STR1## wherein R.sub.1 is an alkyl radical containing up to 3 carbon atoms or is a digoxin or digitoxin residue, R.sub.2 and R.sub.3, which may be the same or different, are alkoxy radicals containing up to 3 carbon atoms or together represent an oxygen atom, X is a cyanomethoxy, succinimide-N-oxy, N-methyl-pyridiniumoxy, 2,4-dinitrophenoxy, 2,4,5-trichlorophenoxy, pentachlorophenoxy, phenylthio, p-nitrophenoxy, n-nitrophenylthio, piperidyl-N-oxy, phthalimido-N-oxy or benztriazol-N-oxy radical and n is 2, 3, 4 or 5, are useful for the preparation of reagents for the investigation of cardiac glycosides (Digitalis glycosides).