It took me but an instant to untwist the thongs with which I had been bound. I dragged myself out of the wreck and stood swaying in the darkness, my head spinning like a gyroscope. A feeling of horrible nausea swept over me and I toppled forward. My outstretched hand brought up against the wooden panels of a door. I slid to my knees, my fingers twisted around the knob. The door opened at the touch; I stumbled, face downward, into a dimly lighted hallway.

For an instant I lay there, too sick and weak to move. Then, as my breath came back to me, I dragged myself to a sitting position.

Betty was shrieking madly.

"Please... oh, please!" she sobbed. "Please... for the love of God, have mercy!... Oh, Bob... come!"

The sound came from a room a short distance down the hall. The terror-stricken voice of my wife pleading for mercy went through me like an electric shock, galvanizing me into action. I shook off the nausea and, pulling myself to my feet, charged like an angry bull.

The door of the room was open, the light streaming out into the hallway. I halted at the threshold, my faculties paralyzed for an instant at the unholy sight which met my horrified eyes.

It was a huge room into which I gazed, made, it appeared, by tearing the partition from between two smaller rooms. Fitted as a laboratory, painted a spotless white, the walls were lined with shelves overflowing with bottles, beakers and test tubes.

In the center was a low divan. Upon it Betty was stretched. She had been nearly divested of her garments. Her slender white arms were drawn above her head. There was scant concealment of any secret of her slim body. Beside her, fastened by a long rope attached to a leather girdle about its middle, was the creature that had attacked us in the darkness. I saw now that it was a monster gorilla.

The rope, attached to a ring in the wall, held it away from her. Its hair-covered, stubby fingers reached out for her—tried to caress her smooth, satiny flesh—tried to fondle her in a diabolical and unholy embrace. It whimpered appealingly, its tiny, bloodshot eyes gloating over her youthful beauty as it strove with all its gigantic strength to stretch the rope which held it from her.

At a table close beside them stood Bixby, a long white smock clothing his emaciated form. He hovered over the delicate apparatus, his long, skinny fingers darting here and there, his cavernous eyes glancing gloatingly at the terrible scene that was being enacted before him.

"In a moment," he crooned soothingly to the whining monstrosity at the end of the rope. "In a moment, my pet. Then I will wield the knife. Her blood will be in your veins and your rich, red corpuscles will go charging through her slim, white body, mixing with her blood. Then... then she will be yours..."

The accursed thing whimpered understandingly. It turned its shaggy head to him for an instant and whined like a dog.

Bixby selected a slender knife from the glittering array on the table. For an instant he held it aloft, examining its razor-sharpness. Nodding with satisfaction, he took a step forward and bent over the nude form on the divan, his sunken eyes searching for the vein he was about to open.

Betty screamed again. In her agony, she turned her head. Her eyes met mine. In them was a look of pathetic appeal. She sensed my weakness—knew that there was but little I could do to save her. Yet her movement broke the spell that seemed to have been cast over me and I charged forward with an angry bellow. Bixby turned as my hands reached for his scrawny throat The blade dropped from his fingers and he lunged for the revolver that lay in an open drawer beside him. Betty screamed. "Bob! Watch out!" she shrieked. I whirled. But too late. I caught an indistinct glimpse of the huge black as he struck. His great fist crashed against my head and I went down like an ox.

I WAS out only for a second. Yet the single blow paralyzed my nerve centers, making it impossible for me to move. Things happened with kaleidoscopic rapidity. As in a trance, I saw the big black leap forward and claw with feverish rapidity at the bindings which held Betty to the couch.

"Jarbo's... she is Jarbo's!" he snarled. "No give to ape-man this time."

Bixby's saturnine face was flushed with anger.

"Leave her alone, damn you!" he roared. "She is the first that he really seemed to care for. Do you think, you fool, that you are going to spoil my great experiment... now?"

He leaped forward, his talon-like fingers grasped around the butt of the gun.

The crazed black pushed him back with a sweep of his huge arm. The old man crashed against the table, upsetting it; the apparatus tumbled over the floor in wild disarray. He dropped to a crouching position, the gun raised, his thin lips drawn back over his teeth in a snarl of anger.

"Leave her alone!" he snapped. The big black took a step forward, his huge fists doubled.

"Jarbo's!" he growled. Bixby fired. The black staggered back as the leaden slug sunk into his vitals. Then he gathered his huge body together and hurled himself forward. His fist crashed against the old man's jaw, bringing the head back with a sudden jerk. Then his great fingers closed around the scrawny throat. There was a snap of breaking bones.

Raising the form of his victim above his head, the burly black threw the old man across the room. Then, turning, he leaped back to Betty.

The ape-man gave vent to a wild, insane roar. He lunged forward, maddened at the sight of blood and the death of his master. Its terrific lunge broke the rope. Jarbo turned to meet the mad rush. They went down together, the ape and the black, clawing, biting, in a battle to the death. The sinewy fingers of the gorilla sought the other's throat— found it. I saw the black's eyes bulge from their sockets under the terrific pressure.

All this, I say, transpired in less time than it takes for me to tell it. Dazed though I was, Betty's frightened scream brought me to my senses. The revolver had fallen almost beside me. I seized it and, jamming it against the hairy head of the horrific monstrosity, pulled the trigger. The apeman's death grip on the black's throat relaxed. He kicked spasmodically, then rolled over... dead.

There was a crash as the front door was forced open. Then a squad of state policemen charged into the room, guns drawn. With them was the attendant at the oil station.

"One of my men found your abandoned car an hour ago," the sergeant in command told me as he assisted me to my feet. "When the attendant at the filling station identified it, we lost no time in getting here. There have been several women missing of late and all clews have centered on this locality. We were just outside when we heard the shots..."

I picked up the surgeons' knife from the floor and cut Betty's bonds. Then, wrapping a cover about her trembling form, I assisted her to a chair. It took me but a moment to tell the officer what had happened.

"That explains the disappearance of the women—up to a certain point," he said thoughtfully. "On the other hand, there are a lot of things I don't understand."

"The black's still alive, sergeant," one of the men who had been prowling through the room, interrupted.

The sergeant bent over the wounded Algerian and called for a first aid kit. As it was brought, he poured a bit of liquor between the thick mutilated lips. Jarbo stirred... opened his eyes.

"Master dead... ape dead," he gasped, his eyes turning on me. "Pretty soon Jarbo die. You keep woman..."

DYING, the big black wheezed out his story to the officers while Betty and I sat in the background shuddering at our narrow escape.

Bixby, a scientist of renown, had been dismissed from his post at one of the great universities because of his fantastic theories and radical experiments.

An anthropologist and biological chemist, Bixby had been obsessed by the idea of fusing blood of powerful lower animals with that of white women—to build up the racial stamina, weakened by the artificialities of modern life.