Olena v. Company, 82 N.H. 408. Cf. Nadeau v. Stevens, 79 N.H. 502. The possibility that the blasting caused the damage could reasonably be found "the most probable possibility disclosed by the evidence," and blasting the most probable cause.

Specifically, appellant argues that the absence of records of sales not taken because of the unavailability of more leatherboard makes any opinion of the witness as to such sales inadmissible. Appellant cites Nadeau v. Stevens, 1920, 79 N.H. 502, 111 A. 749 and Parent v. Nashua Mfg. Co., 1899, 70 N.H. 199, 47 A. 261, in support of its contention. However, these cases hold that on the issue of causation of an accident, if a foundation of evidence to show the existence of certain circumstances is not present, then opinion testimony that such circumstances could have caused the accident is inadmissible.

This evidence, in conjunction with the testimony of the plaintiff's attending physician that her disability was caused by irritation of her lungs from the inhalation of "irritant" gases warranted submission to the jury of the issue of whether the plaintiff's injury was caused by sewer gas. The plaintiff's further contention that sewer gas was not shown to have been present in dangerous quantity, and that therefore the instructions given erroneously permitted a verdict based upon surmise and conjecture (Russell v. Railroad, 83 N.H. 246; Nadeau v. Stevens, 79 N.H. 502), applies with equal force to her own proof of the presence of other gases. A finding that any gas was present in sufficient quantity to cause injury rested only upon the circumstantial evidence of the fact of injury, relied upon by the plaintiff's physicians as a basis for their opinions. If their testimony was sufficient to permit a finding that the plaintiff's condition was due to inhalation of irritant gases, the jury could find that such gases had been present in sufficient quantity. If the jury could not properly accept this testimony so that sewer gas could not be found causal, then the plaintiff's case in chief likewise was lacking in evidence of the presence of any other gas in quantity sufficient to cause injury. We find no error in the manner in which the issue was submitted to the jury.

The defendant contends that this evidence was erroneously received because there was no evidence that the can contained either of the last mentioned substances, and the witness' testimony that either might have caused the explosion rested only upon conjecture upon which a verdict could not properly be founded. See Dade v. Railroad, 92 N.H. 294; Nadeau v. Stevens, 79 N.H. 502. The evidence disclosed however that gasoline was used for various purposes by sectionmen and patrolmen, and in particular to operate motor-driven generators used in tamping the road bed, an operation which had been conducted in the "Wamesit" vicinity during the preceding fall. While the plaintiff's foreman denied that any gasoline would have been left in the section house or was customarily stored there, it did appear that the section houses were commonly used for overnight storage of tools and equipment by the tamping crews. Snow-melting oil which was used in distinctive cans having a long spout with wick at the end was customarily stored at Lowell.

On the contrary, if reasonable men on the evidence could only reach a conclusion on that issue by conjecture, chance, or doubtful and unsatisfactory speculation, it was the duty of the Court to withdraw that issue from their consideration. Deschenes v. Railroad, 69 N.H. 285, 291; Nadeau v. Stevens, 79 N.H. 502; Ahern v. Railroad, 88 N.H. 287; Abell v. Company, 95 N.H. 439, 441. In ruling on defendant's motion, the Court was obliged to consider the evidence for the plaintiff as true and to construe all the evidence most favorably to the plaintiff.

We think, however, that the present case is governed by the more general rule, to which reference is also made in the same opinion, that where the evidence discloses no connection between the injury and the alleged cause except a bare possibility that the former resulted from the latter, there is nothing for the jury where it is also possible that the injury may be due to other causes. Deschenes v. Railroad, supra; Dame v. Company, 71 N.H. 407; Reynolds v. Company, 73 N.H. 126; Clark v. Sharpe, 76 N.H. 446, 447; Nadeau v. Stevens, 79 N.H. 502; Russell v. Railroad, 83 N.H. 246, 249. Some evidence tending to establish not only the possibility but also the probability that excitement and strain resulting from an encounter with suffocating gas aggravated a preexisting physical condition and thereby caused Mr. Ahern's death, was, under the theory of the trial court, a necessary element of the plaintiff's case, and in the absence of such evidence, the finding in his favor cannot be sustained. Petition dismissed.

The record is clear that the plaintiff received a blow on her head, but it is silent as to whether this blow caused her jaws to snap together, or, if it did, that the teeth struck out of alignment. From this lack of evidence the defendant argues that a finding that the plaintiff's tooth was broken in the accident would be one based, not upon evidence, but upon guess or conjecture. The defendant's position would be well taken if the above evidence was all that there was in the case on the question of the cause of the plaintiff's injury. Nadeau v. Stevens, 79 N.H. 502. But the case at bar differs from the case last cited in that here there is other evidence on the subject. The plaintiff testified that before the accident her teeth were in excellent condition and gave her no trouble. This testimony was corroborated by her dentist.

Since there was no evidence on which to base a finding that the death of Mrs. Davis was due to the fact that the factory doors did not open outward it follows that the defendant's motion for a directed verdict should have been granted. Deschenes v. Railroad, 69 N.H. 285; Dame v. Car Works, 71 N.H. 407; Proulx v. Goodrich, 77 N.H. 297; Vaughan v. Railroad, 78 N.H. 615; Nadeau v. Stevens, 79 N.H. 502; Russell v. Railroad, 83 N.H. 246. In view of this conclusion it is unnecessary to consider the questions of law raised by the defendant's other exceptions and the order here must be

" The question is whether this can be deemed a "positive opinion" upon which a finding of life long disability could be based. Nadeau v. Stevens, 79 N.H. 502, 503. The issue to be proved was one upon which "common knowledge furnishes no criterion for judgment and evidence becomes indispensable."

Consequently in a case like the present one which calls for a determination of those limits, common knowledge furnishes no criterion for judgment and evidence becomes indispensable, for it has been held repeatedly in this state that "the law does not permit the jury to find a verdict upon surmises and conjectures, but it must be founded upon some substantial evidence." Nadeau v. Stevens, 79 N.H. 502, 504, and cases cited. The law "requires an open, visible connection between the principal and evidentiary facts and the deductions from them, and does not permit a decision to be made on remote inferences."