peroxide of lead and blackoxide of manganese. I dried the skin of a frog and touched it with adrop of solution containing a single one of the tiny crystals, whenstrong tetantic convulsions ensued and the animal died in ten seconds.At last, however, after many other experiments, the idea occurred to methat it was an alkaloid of some plant unknown in modern toxicology. Iwas, of course, aware of the action of the calabar bean of the WestCoast of Africa, the akazga, the datura seeds of India, and such-likepoisons, but this was certainly none of these. It was a substanceterribly deadly--the only substance that could strike death through thecuticle--utterly unknown to us, yet the most potent of all secretpoisons."
"And how did you determine it at last?"
"By a reference I discovered in an ancient Latin treatise on poisonsfrom the old monastery at Pavia, now in the British Museum. It gave mea clue which ultimately led me to establish it as the alkaloid of thevayana bean. This bean, it appears, was used in the tenth and eleventhcenturies by a sect of the despotic Arab mystics called the Fatimites,who had made Cairo their capital, and held rule over Syria as well asthe northern coast of Africa. The last Fatimite was, at a later date,dethroned by Saladin, conqueror of the Koords, and who opposed Richardthe First of England. The poison, introduced from Egypt into Italy, wasknown to the old alchemists as the most secret means of ridding one ofundesirable acquaintances. Its effect, it was stated, was the mostcurious of any known drug, because, for the time being, it completelyaltered the disposition of the individual and caused him to give way toall sorts of curious notions and delusions, while at the same time hewould be entirely obedient to the will of any second person. Afterwardscame fierce delirium, a sensation as though the lower limbs were frozen,complete loss of power, exhaustion, and death. But in modern toxicologyeven the name of the vayana was lost.
"My first step, therefore, was to seek assistance of the great botanistwho is curator of Kew Gardens, and, after considerable difficulty andmany experiments, we both arrived at the conclusion that it was the beanof a small and very rare plant peculiar to the oasis of the Ahir in thesouth of the Great Sahara. At Kew there was a stunted specimen, but ithad never borne fruit, therefore we both searched for any other specimenthat might exist in England. We heard of one in the wonderful gardensof La Mortola, near Mentone, and, after diligent inquiries, discoveredthat a firm of importers in Liverpool had sold a specimen with the beansin pod, which was delivered to a person named Turton, living inBishop's-wood Road, Highgate, and planted in a small greenhouse there.I have not been idle," he added with a grin. Then, taking from a drawerin the table before him a photograph, he handed it to me, saying, "Ihave been able to obtain this photograph of Mrs Turton--the lady whopurchased the plant in question."
He held it out to me, and in an instant I recognised the face. It wasthat of the woman who had crept so silently through the rooms atAtworth--La Gioia!
Briefly, I told him all that had transpired on that night, and declaredthat I recognised her features, whereat he grunted in satisfaction.
"You have asked me to try and solve the mystery, and I have done so.You will find this woman living at a house called `Fairmead' in the roadI have indicated. I have not only established the cause of thephenomena, but I have, at the same time, rediscovered the mostextraordinary and deadly substance known in toxicology. As far as thepresent case is concerned, my work is finished--I have succeeded inmaking some of the vayana alkaloid. Here it is?" and, taking a smallyellow glass tube, securely corked and sealed, he handed it to me.
In the bottom I saw half a grain of tiny white crystals. I knew now whyhe was wearing gloves in his laboratory.
"And have you seen this woman?" I asked the queer old fellow, whosecareful investigations had been crowned with such success. "How did youknow, on the following day, that it was La Gioia who had come in theguise of a dressmaker?"
"I have seen her, and I have seen the plant. It is from one of thebeans which I secured secretly that I have been able to produce thatsubstance. I knew her by overhearing a conversation between Miss Wyndand her cousin on the following morning."
"And the woman is in ignorance that you know the truth?"
"Entirely. I have finished. It is for you now to act as you thinkfit."
I expressed admiration for his marvellous patience and ingenuity insolving the mystery, and, when I left, it was with the understandingthat, if I required his further assistance he would willingly render it.
CHAPTER THIRTY.
"LA GIOIA."
On the following afternoon, in response to a telegram I had sent toBeryl, she accompanied me to Highgate to face La Gioia. Now that I hadsuch complete evidence of her attempts to poison, I did not fear her,but was determined to elucidate the mystery. Beryl accompanied merather reluctantly, declaring that, with such power as the woman held,our lives were not safe; but I resolved to take her by surprise, and torisk all. After leaving Hoefer I had sought an interview with thedetective Bullen, and he, by appointment, was in the vicinity of thehouse in question, accompanied by a couple of plain-clothessubordinates.
We stopped our cab in Hampstead Lane, and descending, found that theBishop's-wood Road was a semicircular thoroughfare of substantialdetached houses, the garden of each abutting upon a cricket-ground inthe centre, and each with its usual greenhouse where geraniums werepotted and stored in winter. On entering the quiet, highly-respectablecrescent, we were not long in discovering a house with the name"Fairmead" inscribed in gilt letters upon the gate, while a littlefurther along my eyes caught sight of two scavengers diligently sweepingthe road, and, not far away, Bullen himself was walking with his backturned towards me.
On our summons being responded to I inquired for Mrs Turton, and wewere shown into the drawing-room--a rather severely furnished apartmentwhich ran through into the greenhouse wherein stood the rare plant.Hoefer had described it minutely, and while we waited, we both peeredinto the greenhouse and examined it. The plant standing in the fullsunlight was about two feet high, with broad, spreading leaves of arich, dark green, and grew in an ordinary flower-pot. Half-hidden bythe leaves, just as Hoefer had said, we saw some small green pods, longand narrow--the pods of the fatal vayana.
Ere we had time to exchange words the door of the room opened, and therestood before us the tall, dark-robed figure of "La Gioia." Her hardface, pale and expectant, showed in the full light to be that of a womanof perhaps forty, with dark hair, keen, swift eyes, thin cheeks, andbony features--a countenance not exactly ugly, but rather that of awoman whose beauty had prematurely faded owing to the heavy cares uponher.
I was the first to address her, saying, "I think, madam, you aresufficiently well acquainted with both of us not to need any formalintroduction."
Her brow contracted and her lips stood apart. Then, without hesitation,I told her my name and that of my companion, while the light died fromher careworn face and she stood motionless as one petrified.
"We have come here, to you, to seek the truth of the conspiracy againstus--the plot in which you yourself have taken part. We demand to knowthe reason of the secret attempts you have made upon the lives of bothof us."
"I don't understand you," she answered with hauteur.
"To deny it is useless," I said determinedly. "The insidious poison youhave used is the vayana, and the only specimen in England bearing fruitis standing there in your greenhouse." And as I uttered those words Iclosed the door leading beyond, and, locking it, placed the key in mypocket.
Her teeth were firmly set. She glanced at me and tried to deny theallegation, but so utterly was she taken aback by my sudden denunciationthat words failed her. A moment later, however, taking several pacesforward to where we stood, she cried with a sudden outburst ofuncontrollable anger--
"You--Beryl Wynd--I hate you! I swore that you should die, and youshall--you shall!"
But I stepped between them, firm and determined. I saw that this womanwas a veritable virago, and that now we had cornered her so neatly shewas capable of any c
rime.
"I demand to know the truth!" I said in a hard, distinct voice.
"You will know nothing from me," she snarled. "That woman has betrayedme!" she added, indicating Beryl.
"Your evil deeds alone have betrayed you," I responded, "and if youdecline to tell me anything of your own free will, then perhaps you willmake a statement to the police when put upon your trial for attemptedmurder."
"My trial!" she gasped, turning pale again. "You think to frighten meinto telling you something, eh?" she laughed. "Ah! you do not know me."
"I know you sufficiently well to be aware that you are a clever andingenious woman," I replied. "And in this affair I entertain a beliefthat our interests may, after all, be mutual."
"How?"
"Tattersett