简和两位保姆之所以突然不见，原来是因为，米尔德里德早就知道墙内部的秘密，她趁着主人们外出揭开了这个秘密，进入到墙内部……
Through consideration for the nerves and perhaps the credulitya of the reader，it may be advisable at this juncture to go a little back in our story and relate the circumstances which led to the present perplexing crisis.A great detective once said that "every mystery has a simple solution"—meaning，of course，that the solution is simple when once discovered.
Therefore，the puzzling mystery of the disappearance of babyJane and her two nurses，followed later by the vanishment of Mr.Bulwer Runyon，was due to the one—time idiosyncracyb of a certain Se？or Cristoval，happily deceased，rather than to any supernatural agency.
Until now we have only known Mildred Travers，as she called herself，in a casual way.We know that she was considered a competent nurse and had proved her capability in the care of baby Jane.Also we know that she was silent andreserved and that her eyes bore an habitual expression that was hard and repellent.Without being able to ？nd any especial fault with the girl，no one was attracted toward her—alwaysexcepting the baby，who could not be expected to showdiscrimination at her tender age.
A little of Mildred's former history had escaped her，but not enough to judge her by.She had once lived in Southern California，near this very place.She had visited this house frequently with her father，when a small child，and old Se？or Cristoval had confided to her some of the secrets ofthe mansion.That was all.What had become of friends and family，how she went to New York and studied nursing，or what might account for that hard look in her eyes，no one now acquainted with her knew.
The Mexican girl，Inez，was nearly as peculiar andunaccountable as Mildred.There was no mystery about her，however，except that she was so capable and intelligent，considering her antecedents.Inez'people lived in a small town in another part of the county and the girl was one of a numerous brood of children whose parents were indolenta，dissipatedb and steeped in ignorance.When fourteen years old she had left home to work for some of the neighboring ranchers，never staying in one place long but generally liked by her employers.The woman who had recommended Inez to Mrs.Weldon said she was bright and willing and more intelligent than most Mexicans of her class，but that she possessed a violent temper.
Louise had seen little evidence of that temper，however，for Inez from the ？rst loved her new mistress and idolized the baby.It was only after Mildred came to supplant her，as she thought，that the girl developed an unreasoning，passionate hatred for the other nurse and was jealous of every attention Mildred lavished upon the little one.
The baby was impartial.She laughed and held out her chubby ？sts to either nurse，perhaps realizing that both were kind to her.It was this that made Inez so furious and causedMildred to disdaina the Mexican girl.The two were at sword's points from the first，although after a little Mildred made an attempt to conciliate Inez，knowing that the untutored Mexican was by nature irresponsible and jealous，but withalb loving and generous.
Inez did not respond to these advances，but as the days passed she became less sullenc when in the presence of Mildred，and at times，when busied over her duties，so far forgot her animosityd as to converse with her in her old careless，unaffected way.Only Mildred was able to note this slight change，and it encouraged her to believe she might win Inez'con？dence in the end.Inez herself did not realize that she had changed toward the "witch—woman，"and when brooding overe her fancied wrongs hated Mildred as cordially as ever.
On the day when the Weldons and their guests rode into town，the two nurses had indulged in a longer and more friendly conversation than usual.It began by Mildred's chidingf the Mexican for taking baby to the quarters unknown to her，as she had been obliged to follow to see what had become of the child.Inez retorted by accusing Mildred of spying upong her.Their return to the house was anything but friendly，and Inez flatly refused to obey such instructions as Mildred gaveher for the care of baby.She even walked out of the court in a temper and was gone for an hour.Then she stole in，a little ashamed of her revolt，but still de？ant and rebellious.
They were in the nursery and Mildred pretended not to notice her assistant's mood.
"I have prepared two bottles of baby's food，"said she.
"Please place one in the hollow of the wall，in your room，to keep cool until we need it.""I won't！"said Inez.
"Why not？"asked Mildred quietly.
"Because you are witch—woman，"cried the Mexican；"because you use bad magic to make hollow in wall；because you try to make baby witch—woman，like yourself，by keeping her milk in the witch—place；because—because—I hate you！"she concluded with a passionate stamp of her foot.
Mildred looked upon the girl pityingly as she crossed herself again and again as if in defiance of the supposed witchcrafta.The poor girl sought by this method to ward off any evil charm Mildred might attempt in retaliationb，and the action nettled the trained nurse because the unjust accusationwas so sincerely made.
She slowly rose and taking the bottle of milk carried it herself to the hollow in the wall and placed it upon a shelf.Then，returning，she stood before the petulantc，crouchingMexican and said gently：
"Were I truly a witch，Inez，I would not be working as a nurse—just as you are.Nor do I know any magic，more than you yourself know.""Then how you know about that hole in the wall？"demandedInez.
"I wish you would let me explain that.Indeed，I think a good talk together will do us both good.Take this chair beside me，and try to believe in my good will.I do not hate you，Inez.I wish you did not hate me."Inez slowly rose from the floor and seated herself in the chair，turning it so that she could eye Mildred's face as she spoke.