Claude S. Tuttle and Watts Gentry for appellant. (1) The court erred in overruling the demurrer to the evidence at the close of all the evidence in the case for the following reasons: (a) When, as in the case at bar, a petition charges specific acts of negligence, the rules res ipsa loquitur does not apply, even if it would have been applicable under a general charge of negligence. One or more of the specific acts of negligence must be proved by substantial evidence, and recovery may be had, if at all, only upon proof of such specific act or acts. State ex rel. Anderson v. Hostetter, 140 S.W.2d 21; Pedio v. Posterny, 102 S.W.2d 600; State ex rel. City of Macon v. Trimble, 12 S.W.2d 727; Kuhlman v. Water, L. T. Co., 307 Mo. 607, 271 S.W. 788; Morrow v. Mo. Gas Elec. Co., 315 Mo. 367, 286 S.W. 106; Poindexter v. Mt. Ry. Cons. Co., 269 Mo. 114, 189 S.W. 808. Plaintiff's instructions having eliminated all but one of specific allegations of negligence, only that one will be considered by this court in passing on the demurrer to the evidence. Krinard v. Westerman, 279 Mo. 680; Henry v. First Natl. Bank of K.C., 115 S.W.2d 121. Even that allegation was disproved by plaintiff. (b) The evidence leaves the cause of the explosion in such uncertainty that only by the exercise of speculation and mere guesswork could a jury arrive at the cause thereof. Verdicts based upon mere speculation or guesswork cannot be allowed to stand. State v. Trimble, 12 S.W.2d 727; Brown v. St. Louis County Gas Co., 131 S.W.2d 354; Bates v. Brown Shoe Co., 116 S.W.2d 30; Muellen v. Lowden, 124 S.W.2d 1152; Brown v. Mulford Co., 198 Mo. App. 586; Carnahan v. R. Co., 88 S.W.2d 1027. (c) It was incumbent upon plaintiff to show a causal connection between one or more acts of negligence alleged in plaintiff's second amended petition and the explosion to show that at least one such act was a proximate cause of injury or death, but plaintiff failed to meet that burden; hence she made no case justifying submission of her case to the jury. State ex rel. Trading Post v. Shain, 116 S.W.2d 99; Henry v. First Natl. Bank, 115 S.W.2d 121; Wecker v. Grafeman-McIntosh Ice Cream Co., 31 S.W.2d 974; Warner v. Ry. Co., 178 Mo. 134; Harper v. St. L. Mer. Bridge Ry. Co., 187 Mo. 575; See cases under Point 1 (b), (d) It would have required far more than ordinary care on the part of the city of St. Charles, through its proper agent, to have foreseen that an explosion might occur which could result in injury or death at the time in question. In fact it would almost have required the gift of prophecy, which corporations are not required to possess or exercise. A defendant is not required to foresee occurrences which are so unusual and extraordinary that no reasonably prudent person could anticipate them. Ray on Negligence of Imposed Duties, p. 133; Fuchs v. St. Louis, 167 Mo. 620; Kennedy v. Quarry Co., 291 S.W. 475; Ward v. Ely-Walker D.G. Bldg. Co., 248 Mo. 348; Wecker v. Grafeman-McIntosh Ice Cream Co., 31 S.W.2d 974; Mattingly v. Broderick, 36 S.W.2d 415; Cole v. Uhlmann Grain Co., 100 S.W.2d 311; Webb's Pollock on Torts, p. 45; Jones v. Ry Co., 63 S.W.2d 94; Nelson v. Heinz Stove Co., 8 S.W.2d 918; Mann v. Pulliam, 127 S.W.2d 426; State ex rel. v. Lusk, 271 Mo. 463; Graney v. Road Co., 157 Mo. 666; Mullen v. Lowden, 124 S.W. 1152; Carnahan v. Railway Co., 338 Mo. 23, 88 S.W.2d 1030; Amer. Brew. Assn. v. Talbot, 141 Mo. 674; De Moss v. K. Rys. Co., 246 S.W. 566; McCullom v. Winnwood Amusement Co., 59 S.W.2d 693; Williams v. Terminal Ry. Assn., 98 S.W.2d 651; Lotta v. K.C. Pub. Serv. Co., 117 S.W.2d 296; Ilgenfritz v. Mo. Power L. Co., 101 S.W.2d 723; Nephler v. Woodward. 200 Mo. 179; Luettecke v. St. Louis, 140 S.W.2d 45; State ex rel. Trading Post Co. v. Shain, 116 S.W.2d 99; Hayes v. Kresge Co., 100 S.W.2d 325; Federal Cold Stor. Co. v. Pupello, 139 S.W.2d 996; Rose v. Thompson, 140 S.W.2d 824. (e) Mere proof that one of two or more causes, for one of which defendant would be liable and for the other of which it would not be liable, produced the injury does not satisfy the requirement of the law which is that the evidence must point definitely to the real cause of the accident, and there must be substantial evidence clearly indicating that the proximate cause was a negligent act on the part of the defendant. Such evidence was wanting in this case. Bates v. Brown Shoe Co., 116 S.W.2d 31; Fritz Groh v. Railroad, 243 Mo. 62; Goransson v. Ritter Connolly Mfg. Co., 188 Mo. 300; Brown v. Mulford Co., 198 Mo. App. 586; Coin v. Lounge Co., 222 Mo. 488; Warner v. Railway, 178 Mo. 134; Sharp v. Stuebner Co., 300 S.W. 559; Maupin v. Amer. Cigar Co., 84 S.W.2d 218; Wolf v. Chem. Co., 81 S.W.2d 323; Cole v. Uhlmann Grain Co., 340 Mo. 277, 100 S.W.2d 311; Evans v. Malsman Cons. Co., 122 S.W.2d 924. (f) Under the undisputed evidence in this case it appears that if sewer gas caused the explosion the proximate cause of the explosion in question was the unauthorized and unknown act of some unknown person in putting a large pan or stew pan down through a manhole in the alley north of Decatur Street in the new sewer which blocked the sewer and caused water, sewage and gas to be backed up into the premises where the explosion occurred. There was no evidence tending to show that this act of an unknown person could have been discovered by the city by the exercise of ordinary care. Such an independent act, when the proximate cause of an accident, breaks all connection between previous negligence, if any, on the defendant's part and that of an injured person and relieves the defendant from liability. Kennedy v. Quarry Co., 291 S.W. 479. (2) The court erred in giving Instruction 1 at the request of the plaintiff. Said instruction is set forth in full on pages 114, 115 and 116 of appellant's abstract of record, as well as under this point in our argument in this brief. It is erroneous in the following particulars: (a) The instruction permitted the jury to find that the defendant negligently permitted large and unusual quantities of human excrement and vegetable and organic matter to remain in the sewer and form large quantities of explosive sewer gas therein, although there was no evidence whatever anywhere in the record tending to show, even by inference, that an unusual quantity of human excrement and vegetable and organic matter had been negligently permitted to remain in the sewer. It is error to submit in an instruction facts of which there is no evidence. Dalton v. Railroad, 187 Mo. App. 691; Hearon v. Himmelberger-Harrison Lbr. Co., 227 S.W. 67; Sparkman v. Wabash Ry. Co., 191 Mo. App. 463; Snyder v. Murray, 17 S.W.2d 639; Miller v. Williams, 76 S.W.2d 355. (b) It was error to submit that issue to the jury because such negligence was not specifically alleged as a ground of recovery in any one of the six specific allegations of negligence set forth in the second amended petition. A general allegation on the subject of allowing sewer gas to escape from the sewers being followed by specific allegations as to how it was caused to accumulate and escape, the plaintiff is limited to a recovery on the specific allegations, for they supersede general allegations. Chitty v. Railroad, 148 Mo. 64; Waldhier v. Railroad Co., 71 Mo. 514; Schneider v. Railroad Co., 75 Mo. 295; McNamee v. Railroad Co., 135 Mo. 440. (c) It was error to submit in said instruction the theory that the surface water entering the open manhole at Eighth and Lewis Streets caused the water to be backed up into the basements of the homes along the new sewer line, carrying gas, because the evidence on that subject is so wholly speculative as to be insufficient to support such a theory in the instruction. (d) It was error to assume in said instruction that surface water entering the open manhole at Eighth and Lewis Streets caused the water to back up into the basements of the homes along and connected to said new sewer line because it assumes as a fact a material controverted fact. Schimmelpfenning v. Wells, 24 S.W.2d 154; Boyd v. Kansas City, 291 Mo. 622, 237 S.W. 1001; Althage v. People's Motor Bus Co., 320 Mo. 598, 8 S.W.2d 924; Shepherd v. Century Electric Co., 299 S.W. 90; Ray v. Fayette R. Plumb Co., 287 S.W. 783; Gebhar v. A.C.F. Co., 296 S.W. 446; Barnes v. Baker, 299 S.W. 80; Taylor v. Kansas City, 112 S.W.2d 562; Lackey v. M.K. I. Ry. Co., 264 S.W. 807; Kleinlein v. Foskin, 13 S.W.2d 648; Osby v. Tarleton, 84 S.W.2d 27. E. McD. Stevens, Earl G. Smith and B.H. Dyer for respondent. (1) As against the challenge of a demurrer to plaintiff's case, all evidence in favor of plaintiff's case and all inferences of fact that reasonably may be drawn therefrom must be accepted by the court as true, in light most favorable to plaintiff, and all evidence by defendant except that which supports plaintiff must be disregarded as untrue. Clark v. Atchison Eastern Bridge Co., 24 S.W.2d 143, 324 Mo. 544; Cech v. Mallinckrodt Chem. Co., 20 S.W.2d 509, 323 Mo. 601; Sullivan v. Union Elec. L. P. Co., 56 S.W.2d 97, 331 Mo. 1065. (2) On defendant's demurrer to evidence, inferences unfavorable to plaintiff should not be drawn if others more favorable to plaintiff can be drawn with equal propriety. State ex rel. v. Haid, 28 S.W.2d 97, 325 Mo. 107; Cregger v. St. Charles, 11 S.W.2d 750, 224 Mo. App. 232. (3) The true rule is that what is the proximate cause of an injury is ordinarily a question for the jury. Kidd v. Chicago, R.I. P. Ry. Co., 310 Mo. 1, 274 S.W. 1079; Hogan v. Fleming, 317 Mo. 524, 297 S.W. 404; Cregger v. St. Charles, 11 S.W.2d 750, 224 Mo. App. 232; State ex rel. City of St. Charles v. Haid, 28 S.W.2d 97, 325 Mo. 107. (4) To authorize submission of proximate cause to jury, plaintiff's evidence need not exclude possibility of accident or of a cause for which defendant is not liable, but is sufficient if there is substantial evidence that injury resulted from cause for which defendant is liable. A demurrer should be sustained only when the facts and inferences to be drawn therefrom are so strongly against the plaintiff as to leave no room for reasonable minds to differ. Buesching v. St. Louis Gas Light Co., 73 Mo. 219; Whiteaker v. Railroad, 252 Mo. 438; Cech v. Malliuckrodt Chem. Co., 20 S.W.2d 509, 323 Mo. 601; Clark v. Atchison Eastern Bridge Co., 24 S.W.2d 143, 324 Mo. 433; Young v. Wheelock, 64 S.W.2d 950, 333 Mo. 992. (5) If a defendant is negligent and his negligence combines with that of another or with any other independent, intervenng cause, he is liable although his negligence was not the sole negligence or the sole proximate cause, and although his negligence without such other independent, intervening cause would not have produced the injury. Harrison v. Electric Light Co., 195 Mo. 606, 93 S.W. 951, 7 R.R.A. (N.S.) 293; Hogan v. Fleming, 317 Mo. 524, 297 S.W. 404. (6) It is sufficient to constitute proximate cause that the negligence for which recovery is sought is the cause which sets in motion the chain of circumstances leading up to the injury, and the primary cause will be the proximate cause where it is so linked and bound to the succeeding events that all create or become a continuous whole, with the first so operating on the others as to make the primary cause productive of the injury. Jenkins v. Springfield Traction Co., 96 S.W.2d 620, 230 Mo. App. 1234; Northern v. Chesapeake Gulf Fisheries Co., 8 S.W.2d 982. (7) Proximate cause is commonly and best defined as that cause which, in a natural and continuous sequence, unbroken by any efficient intervening cause, produced the result complained of, and without which the result would not have occurred. Cregger v. St. Charles, 224 Mo. App. 232, 11 S.W.2d 750. (8) The liability of a person charged with negligence does not depend on the question whether, with the exercise of reasonable prudence, he could or ought to have foreseen the very injury complained of, but he may be held liable for anything which, after the injury is complete, appears to have been a natural and probable consequence of his act or omission. Dean v. Railroad, 199 Mo. 386; Benton v. St. Louis, 248 Mo. 98; Funk v. Fulton Iron Works Co., 311 Mo. 77, 277 S.W. 566; Hamilton v. Standard Oil Co., 19 S.W.2d 679, 323 Mo. 531; Gray v. Kurn, 137 S.W.2d 558; Schneiter v. Chillicothe, 107 S.W.2d 112. (9) The doctrine of concurrent negligence is firmly rooted in the jurisprudence of this State. The law is well settled in this State that "a defendant may be liable even if the accident was not caused by his sole negligence. He is liable, if his negligence concurred with that of another or with the act of God, or with an inanimate cause, and became a part of the direct and proximate cause, although not the sole cause." Bassett v. St. Joseph, 53 Mo. 290; Brasch v. St. Louis, 161 Mo. 433; Newcomb v. Railroad, 169 Mo. 409; Harrison v. Kansas City Elec. Light Co., 195 Mo. 606; Carr v. St. Louis Auto Supply Co., 293 Mo. 562; State ex rel. Hauck Bakery Co. v. Haid, 62 S.W.2d 400, 333 Mo. 76; Christiansen v. St. Louis Pub. Serv. Co., 62 S.W.2d 828, 333 Mo. 408: Miller v. United Rys. Co., 155 Mo. App. 528; Neal v. Curtis Co. Mfg. Co., 41 S.W.2d 543, 328 Mo. 417; 45 C.J. 920; Miller v. Union Pacific Ry. Co., 290 U.S. 227; Memphis Consol. Gas Electric Co. v. Creighton, 183 F. 552. (10) Expert testimony as to cause of a given effect or result is substantial evidence. Fritz v. Mfgs. Ry. Co., 124 S.W.2d 603; Wills v. Berberich's Delivery Co., 134 S.W.2d 125; Conduitt v. Trenton Gas Elec. Co., 31 S.W.2d 21, 326 Mo. 133; Kimmie v. Terminal Ry. Assn., 334 Mo. 596, 66 S.W.2d 561. (11) An instruction which places upon plaintiff an unnecessary burden if erroneous, is not prejudicially erroneous and is an error of which defendant may not complain. McIntyre v. St. L.-S.F. Ry. Co., 286 Mo. 234, 227 S.W. 1047; Potterfield v. Terminal Ry. Assn., 5 S.W.2d 447, 319 Mo. 619. (12) A petition charging negligence will be treated as amended in accordance with proof introduced without objection. Ehrlich v. Mittelberg, 299 Mo. 284; Gilliland v. Bondurant, 51 S.W.2d 559; Scott v. St. L.-S.F. Ry. Co., 52 S.W.2d 459; Sternkopt v. Cawein, 63 S.W.2d 443.