(dissenting).
The commission’s determination was based upon two findings or conclusions as follows:
(1) “* * * We cannot state from the medical evidence that the petitioner has proved that coronary sclerosis and cerebral arteriosclerosis are all part of the same pathological picture.”
*249(2) “* * * we cannot conclude that the evidence * * * establishes by a fair preponderance * * * that cerebral arteriosclerosis is an occupational disease of firemen.”
The medical evidence may be summarized as follows: The autopsy listed as a final diagnosis the following:
“Arteriosclerotic cardiovascular disease — perforated ulcer — encepha-lomalacia — pulmonary embolisms.
*****
“Generalized arteriosclerosis.
“Arteriosclerosis grade III to IV of the basal arteries of the brain with old organized and partly recanalized thrombosis of the left medial cerebral artery.
*****
“Coronary sclerosis grade II.
“Small focal scaring of the myocardium of the posterior wall of the left ventricle.
“Arteriosclerosis grade III of the aorta with calcification of the cusps of the aortic valve.
*****
“Arteriosclerosis grade I of both kidneys.”
Subsequent thereto, the attending physician filed a death certificate stating that the immediate cause of the employee’s death was “cerebral thrombosis, encephalomalacia, due to'hypertensive cardiovas disease.”
Dr. Moses Barron, testifying on petitioner’s behalf, expressed the opinion that this thrombosis was a result of extensive arteriosclerosis and that it was related to the nature of employee’s occupation as a fireman. Also that—
“* * * the type of work [of the employee] as described by the two assistant chiefs of the Fire Department, which * * * was a very unusual thorough description of the amount of the emotion and physical strain that is connected with that type of work * * * the tension and the emotional strain and the fact that they are practically never at ease *250especially during the 24 hours when they are working * * *. I felt that this type of work is such that it really helps to explain why arteriosclerosis is so free in these cases, that it came to a point where it was felt that it is an occupational disease.”
He testified that arteriosclerosis is a progressive disease; that different theories as to its causation are. occupation, heredity, racial origin, diet, air pollution, or other causes; that arteriosclerosis may manifest itself or localize in specific areas although producing factors are probably the same; that cerebral thrombosis does not occur without the presence of arteriosclerosis; that in his opinion the employee’s work as a fireman caused the arteriosclerosis of the brain which led to the cerebral thrombosis; and that the most deadly manifestations of arteriosclerosis are in the heart and in the brain.
Dr. Dwight C. Hoag, called by respondents, testified that arteriosclerosis is generalized throughout the population, particularly in older men; that it does not appear specifically in any particular occupational group; that the employee had a marked degree of arteriosclerosis in the cerebral blood vessels; that this was the cause of the thrombosis or blood clot forming; that the arteriosclerosis of the heart was not severe; that possible factors are thought to be diet, obesity, heredity, and hypertension; that arteriosclerosis localized in the heart or brain often can result in cerebral or cardiac accidents; that the two most common occur in the heart and brain; and that the underlying factor in either case may be the same.
Dr. George Berdez, also called by respondents, testified that thrombosis in the cerebral artery had been present 2 or 3 weeks prior to death; that the cause of the thrombosis would be damage to the blood vessels of the brain; that he found arteriosclerosis changes generally, but particularly in the brain; that arteriosclerosis is in part an aging process and the degree varies among individuals; that some theories in regard to causation were heredity, diet, air pollution, and occupation; that arteriosclerosis may manifest itself in various degrees in various portions of the body, including the brain, the heart, the legs, the kidneys, the stomach, or the duodenum.
It should be noted from the foregoing that the testimony of the medi*251cal expert called by petitioner to the effect that arteriosclerosis was the underlying cause of cerebral arteriosclerosis as well as coronary sclerosis was not disputed by respondents’ medical experts. On the contrary, they gave substantial corroboration to such testimony in that both testified that arteriosclerosis might result in either cerebral or cardiac accidents and that the underlying factor in each case may be the same.
This medical testimony finds support in the autopsy filed in connection with the employee’s death which manifested that his arteriosclerosis had affected both his cerebral and his coronary arteries. It seems clear from all such evidence that both coronary sclerosis and cerebral arteriosclerosis are part of the same pathological picture and that both find their origin in general arteriosclerosis. It would follow that the commission’s finding to the contrary would be entirely inconsistent with the undisputed evidence on this issue.
The commission further determined that the evidence failed to establish that “cerebral arteriosclerosis is an occupational disease of firemen.” It is to be noted that this finding has no relationship to the employer’s contention here but is rather a generalization which would eliminate cerebral arteriosclerosis as an occupational disease of firemen in all cases. The only basis for such a determination was the testimony of the two medical experts called by respondents to the effect that arteriosclerosis from which cerebral arteriosclerosis arises is generalized throughout the population and is merely part of an aging process rather than an occupational disease. This testimony is substantially identical to that submitted by the employers’ medical experts in four decisions of the commission (affirmed by this court)1 which related to coronary sclerosis. There such experts testified that coronary sclerosis was not an occupational disease of firemen but found its origin in arteriosclerosis which was common to the population generally rather than to any particular occupational group. There, notwithstand*252ing such testimony, the commission determined that coronary sclerosis was an occupational disease.
In the mind of the commission the distinction between the two situations, one of which related to arteriosclerosis generally and the other of which related to coronary sclerosis, was to be found in Minn. St. 176.011, subd. 15. The commission stated, “[T]he series of cases [on coronary sclerosis] were aided by the legislative statute that the disease was presumed to have been due to the occupation of being a fireman,” the commission pointing out that “[t]here is no such legislative presumption in favor of cerebral arteriosclerosis or generalized arteriosclerosis.”
This distinction would appear to give the statutory presumption involved in the coronary cases an evidentiaiy status which was not intended for it and not relied upon in the cases referred to.2 Accordingly, *253it would seem clear that the decision herein is entirely inconsistent with the decisions in the cases cited and will result in a distinction between the two types of arteriosclerosis which is unjustified. In substance, it will mean that arteriosclerosis arising through stress and strain as experienced by firemen in their occupation as such will be compensable as an occupational disease when its terminal is the heart, but will not be so regarded when its terminal is the brain. There seems to be no logical basis for such a differentiation.
Anderson v. City of Minneapolis, 258 Minn. 221, 103 N. W. (2d) 397; Ogren v. City of Duluth, 219 Minn. 555, 18 N. W. (2d) 535; Kellerman v. City of St. Paul, 211 Minn. 351, 1 N. W. (2d) 378; Schwartz v. City of Duluth, 264 Minn. 514, 119 N. W. (2d) 822.
Ogren v. City of Duluth, 219 Minn. 555, 564, 18 N. W. (2d) 535, 540, stated: “Giving respondent the benefit of the presumption could have resulted in no possible prejudice to relator if the rules laid down in our decisions concerning presumptions were followed by the commission. For lack of affirmative showing to the contrary, we must assume that the commission observed these rules in determining the facts. It is well settled that a presumption is not evidence, but is rather a rule of law dictating decision on unopposed facts and shifting the burden of going forward with the evidence. Ryan v. Metropolitan L. Ins. Co. 206 Minn. 562, 289 N. W. 557. The presumption obtains until substantial proof to the contrary is introduced. Then it ceases and vanishes from the case. The case is then to be decided by the trier of fact the same as if the presumption had never existed. State v. One Buick Sedan Automobile, 216 Minn. 129, 12 N. W. (2d) 1; Roberts v. Metropolitan L. Ins. Co. 215 Minn. 300, 9 N. W. (2d) 730; Duff v. Bemidji Motor Service Co. 210 Minn. 456, 299 N. W. 196. Here, the employer introduced contradictory proof sufficient to overcome the presumption. Respondent introduced proof sufficient to sustain it. In short, the presumption, if applied according to our rules, was only a tentative rule of decision until displaced by the proofs to the contrary. At that juncture it had served the only purpose of a presumption— it had become functus officio, so to speak, and disappeared from the case. As said in the Ryan case (206 Minn. 570, 289 N. W. 561), ‘The presumption, as rule of law compelling decision, was dispelled by the evidence.’ The process of decision occurred after the presumption had vanished from the case. The fact was then determined upon all the evidence without considering the presumption as evidence. Hence, the decision cannot be said to be the result of applying the presumption to the evidence.”