Mr. Justice Burwett
delivered the opinion of the Court..
This is an appeal by the widow and child of a. deceased employee of the defendant from the denial of compensation to them in a workmen’s compensation case.
Vessie Kaylor, the employer; was engaged in cutting, sawing and hauling timber. The deceased employee, Jefferson Albert Milstead, had been in his service for about a year or more at the time of his death. His duties varied according to the needs of his employer.
On July 9, 1946, the deceased was assisting others in loading timber (stay bolts) on a trailer. As he was attempting to load a piece of this timber he “fell over” and “he was lying there with his chest going up and down that way, — and I went there and he was dying”. After the deceased had fallen, as above described by. *646one of the witnesses, this witness called a doctor. By the time the doctor arrived, the deceased was dead.
At the time of this occurrence it was extremely hot— “awful hot”; “terrible hot”.
The record shows without contradiction that the deceased employee was a strong', able-bodied, healthy man who had never had sinking- spells or any form of heart trouble. It is the theory of the widow and child that the death of the deceased employee was due to heat prostration or sunstroke brought about by the employee working in this extremely hot weather. The doctor who was called and arrived within a few minutes after death, noted on the death certificate that death was “due to probable heart attack.”
•No medical testimony was offered by either side. The .petitioners contented themselves by showing the above detailed facts. The defendant introduced a certified copy of the death certificate and contented himself on the question of the cause of death with this.
The trial judge dismissed the petition because “the plaintiff failed to show by a greater weight of the evidence that Jefferson Albert Milstead died from heat prostration arising out of his employment . . . but its cause is left to speculation;”
In so far as we are advised it is a universal rule in workmen’s compensation eases, as in common-law actions for personal injuries and in civil actions generally, that the burden of proof is on the claimant to prove his case in all its parts by a preponderance of the evidence. "We on appeal “do not reweigh the evidence, but search the record only so far as is necessary to determine that there is material evidence to support the finding of the trial judge.” Anderson *647v. Volz Const. Co., 183 Tenn. 169, 191 S. W. (2d) 436, 438.
The holding of the trial judge here is that the plaintiff has failed to carry this burden and show that the death of Milstead was occasioned by an accident arising out of and in the course of his employment.
“This court has sanctioned the proposition that, where an employee is found dead at his post of labor, without direct evidence as to the manner of his death, an inference may arise of an accident springing out of and in the course of his employment.” Home Ice Co. v. Franzini, 161 Tenn. 395, 32 S. W. (2d) 1032, 1033. In other words a prima-facie case for the claimant is thus supported. When such a prima-facie case is thus made out the burden shifts to the employer to produce evidence to overthrow such a prima-facie case. Shockley v. Moristown Produce & Ice Co., 158 Tenn. 148, 11 S. W. (2d) 900.
In the instant case the claimant makes such a prima facie case. It is shown without dispute that the employee while at his work in loading this timber on a very hot July day fell and after a few minutes died. It is also shown without dispute that the employee was a strong, healthy, able-bodied man. The evidence negatives any other cause of death except that as claimed. According to the recognized definitions of the terms, “heat prostration, sunstroke or heat exhaustion, death might reasonably have resulted.
“Heat exhaustion, heat stroke, which occurs usually among workers in furnace rooms, in bakeries, foundries, etc., but it also occurs in those exposed to the sun’s heát. ' The temperature becomes subnormal, accompanied by depression or collapse.
*648“Heát prostrátion. The same as heat exhaustion!
“.Sunstroke. A condition caused by exposure to the sun which is often fatal. It is marked by prostration, á high temperature of the skin, convulsions, and coma. ’ ’ Maloy Medical Dictionary for Lawyers.
Under the facts herein in view of the above definitions we feel that the claimant has certainly made out such a case as requires the employer to go forward and negative this prima facie case. This may either be done by showing the cause of death or by showing other causes equally probable.
Death caused by “heat prostration, sunstroke or heat exhaustion” is compensable in this state. Patten Hotel Co. v. Milner, 145 Tenn. 632, 238 S. W. 75, King v. Buckeye Cotton Oil Co., 155 Tenn. 491, 296 S. W. 3, 53 A. L. R. 1086.
The only evidence offered to counter the case made for the claimant is the certified copy of the certificate of death. This shows that death was’ “due to: probable heart attack.” This certificate is “prima facie evidence of the facts therein stated.” Code, section' 5827Ü2
We are to bear in mind that this is not an action in tort but for compensation as an incident of a contract of employment.
We have here two conflicting presumptions, one of which is said to offset the other so as to make the cause of death conjectural. This is an erroneous legal conclusion. It is a well established rule that these presumptions “should be measured and that the weaker should be deemed to be overcome by the stronger.” 20 Am. Jur., Evidence, section 163; Nichols v. Mutual Life Ins. Co. of N. Y., 178 Tenn, 209, 215, 156 S. W. (2d) 436.
*649Recognizing this distinction, it is the duty of the Conrt to consider the probative force of the respective presumptions.
The presumption or prima facie case made out oh behalf of the petitioners is based on facts shown (1) that the deceased died on his job; (2) that he was a strong, able-bodied man not subject to heart attacks, and (3) that his death under the circumstances was readily attributable to a compensable injury.
On the other hand, the cause of this death is merely shown by the defendant to be “due to probable heart attack. ’ ’ This fact is not testified to by any individual, but is merely a statement made by a doctor in a death certificate. By statute “facts” stated in the certificate are “ prima facie” evidence. The statement here made is not a fact but a speculation. This doctor did not see the deceased until after his death. There is no showing of any investigation by the doctor on which this statement is based. The quoted statement in itself is weak and shows grave doubt. It was, at most, a mere conjecture or possibility.
Our conclusion is that the evidence relied on to establish the rebuttal fact that the deceased died of a heart attack is not sufficient to overcome the case made out by the petitioners.
The defendant, Kaylor, had actual knowledge of the deceased employee’s death within a very few minutes after he died, as herein set forth. The defendant knew the circumstances under which the employee died. He then and there had an opportunity to make any and all investigation humanly possible to ascertain the cause of death. According to this record he made no such investigation. Tinder these facts the trial judge correctly held that written notice under the act (Code section 6872) *650was excused. Under the authority of Tennessee Products Corporation v. Gravitt, 182 Tenn. 54, 56, 184 S. W. (2d) 164, there being some evidence upon which to base this finding, we must affirm the trial judge therein.
For the reasons expressed herein, we must reverse the judgment below and remand the case to ascertain the amount to which claimants are entitled under the Workmen’s Compensation Act, and to enter a judgment accordingly.
All concur.