Antidote to Venom by Freeman Wills Crofts

George Surridge was the highly respected director of the Birmington Zoo. In this position, he had a good social position in the city, a good salary, and a comfortable house to live in. Unfortunately George and his wife Clarissa did not get along very well. George believed that she wanted more money than it was possible for him to provide. George was a member of a gambling club, and George sometimes lost more money than he could afford, but he would sometimes recoup his losses. Then one day at the zoo, George met a charming woman, Nancy Weymore, who was a widow. She and George developed a friendship, and George gave up his golfing afternoon to be with Nancy.

Meanwhile at the zoo,  George had to deal with some difficulties. An  employee, the night watchman John Cochrane, needed to leave the zoo for a short time to give his sick wife her medicine. George encountered Cochrane on his way back, and insisted the Cochrane should be fired. Also, professor Burnaby, a retired professor, who was still conducting his research on the effect of snake venom on cancer cells with resources of the snake house at the zoo, caused zoo employees to worry about the possibility that he was becoming somewhat senile, and George found it necessary to restrict Burnaby's access to the snake collection.

George and Nancy conceived the idea of purchasing a charming cottage where she could live, and where George could easily come and visit. George's hope for money rested on the belief that his elderly aunt would shortly die. Her doctor had told George that she had not long to live. George was her only heir. His aunt did indeed die, but George found out there would be quite a while until he could get access to her money. He had promised the realtor that they would purchase the cottage and he needed money. Then George was approached by Capper, who was the solicitor responsible for settling his aunt's estate and a nephew of Burnaby. He was also Burnaby's only heir. Capper proposed to George that they cooperate in a very complicated plot to murder Burnaby by a method which would be impossible to detect. This plan would give George the money much more rapidly than he was getting it from his aunt's will.

The reader will find out about George's part in this plan as he carries out the necessary steps George does not know, however, how Capper carried out his part in the murder.  Burnaby does die, and an inquest is held. and his death is ruled an accident. A casual conversation brings this death to the attention of Chief Inspector  Joseph French of New Scotland Yard. French reads the evidence and a transcript of the coroner's trial, and finds something which he thinks has been overlooked. He goes to Birmington to look into Burnaby's death, and unravels a remarkably complex method of committing a murder.

This book was published by Freeman Wills Crofts in 1938. At this time, he had already become a well known and popular mystery novelist. In this novel, he tried to combine the inverted detective story in which the reader knows who and how the murderer committed the crime, and the direct story in which the detective determines who the murderer was and how the crime was committed. This book is quite detailed, and the character of George Surridge is much more developed than is done in mystery novels of this period.