This is an appeal by the self insurer in a workmen’s compensation case from a decree awarding compensation to the dependents of one Sevigny. The single member found that there existed “a probable causal relationship between the employee’s death and his industrial injury” of November 21, 1955, which finding was in effect *748 adopted by the reviewing board. The decision of the board also considered motions by the self insurer to recommit and to correct the transcript. Other than correcting the Christian name of the self insurer’s expert, both motions were denied.
The employee, Royal E. Sevigny, while employed as a cook by Harvard University, received a cut on his right index finger when a knife which he was using to slice meat slipped. He received treatment the same day at the Harvard University Employees’ Clinic and additional treatment on November 23, 25, 28, 29 and 30, and December 1, 1955. On the last mentioned date he was admitted to the Faulkner Hospital and was treated for a staphylococcus aureus infection of the second metacarpophalangeal joint of his right hand. The wound was incised and drained and he was discharged on December 9, 1955. He thereafter was given physiotherapy for his finger and it was examined at the clinic on several dates through January 17, 1956. There was oral testimony that about a month after his return from his first visit to the hospital, the employee, who had always been active about the house, had become listless and complained of being tired. His gums were bleeding and his palate was large and swollen. On Sunday, January 22,1956, he remained in bed, too tired to accompany his wife to church as he usually did. The next day she saw that his face was swollen and he had a cough and a temperature. He was then seen by the family physician on January 23, 1956, and was readmitted to the hospital on the same day where a diagnosis of monoblastic leukemia was made. He died on January 25, 1956.
The question presented by this appeal is whether or hot there was sufficient proof of a causal relation between the contracting of monoblastic leukemia and the preceding injury. The case seems not to have been heard on any issue of acceleration or aggravation of leukemia as a preexisting disease. Cf.
Ralph’s Case,
The findings and decision of the single member as affirmed
*749
by the reviewing board are to be sustained wherever possible unless they are wholly lacking in evidential support or contain an error of law.
Lysaght’s Case,
As the findings of the single member and the board are based on the expert testimony of Dr. Stefanini, who was called as a witness by the dependents, it is necessary to review his testimony. This witness testified that acute leukemia is a form of malignant cancer with wild growth which affects the bone marrow and results in an increase in the white blood cells and a reduction of normal red blood cells so that a patient develops anemia. He expressed his opinion that the employee was suffering from monoblastic leukemia which is known for a very rapid course so that a patient survives for a shorter time after attack than with other types of leukemia. When asked his opinion as to the causal connection of the injury and the ensuing infection with the resultant death by leukemia he replied that “there is a possible causal relationship between the infection and the development of acute leukemia in this case.” If the evidence stopped at this point the opinion would be no more than mere speculation or conjecture and would have to be disregarded.
Falco’s Case,
The dependents’ expert finished his direct examination by answering a hypothetical question whether the death of the employee was a probable result of the injury on November 21, 1955, after being informed that “probable” in the question meant “more than possible.” The witness answered, “It was a probable outcome.” On cross-examinatian the witness was asked whether it was not a matter of speculation to state that the infection could have caused the leukemia. To this question the witness replied that they have a man (the deceased) who is well up to November 21, 1955, and a blood count is taken somewhere between December 1 and December 9, and he is still perfectly well as far as his blood is concerned, then in a matter of six weeks “he explodes in a disease” which they know can develop very suddenly. When asked for a yes or no answer, the witness replied that he did not think he could answer, but if counsel wanted a direct answer “he will say yes”
1
(i.e., it is not a matter of speculation). This testimony, highly ambiguous, together with a previous answer that the leukemia was more than a possible result of the infection, could have been
*751
regarded by the board as testimony to the effect that the witness believed that the death by leukemia was more likely than not a result of the staphylococcus infection. The fact that the witness further testified that “It is not unlikely [that the infection would have been the cause of the onslaught of acute leukemia in Mr. Sevigny’s case]]” confirms this interpretation.
DeFilippo's Case,
However, it is contended by the self insurer that since the state of medical knowledge as to the causes of leukemia is indefinite, any opinion based on such medical knowledge is of necessity merely speculative and conjectural. See
Hogan
v.
Stovall Drilling Co. Inc.
. During the examination of Dr. Stefanini frequent references were made to treatises written by medical authorities dealing with the relationship between bacterial infection of the type admittedly incurred by the employee and acute leukemia of the kind which caused his death. Copious abstracts of these publications were attached to the motion to recommit which was presented and considered by the board and which in reality was a motion for a new trial. These abstracts were expressly made a part of the record by order of the board. No question is raised as to their accuracy. See
Bacon
v.
George,
The expert for the dependents testified that he had seen five hundred cases of leukemia and that in six of them an “infection was a possible producing cause” (emphasis supplied). He also stated that the opinions of medical authorities are about equally divided whether there is a causal connection between infection and leukemia (“50-50 all along the line”). He apparently recognized that there was less evidence that bacterial infection might be a contributing cause of leukemia than that viruses might be such a cause. 1 The expert relied considerably on medical writings, set forth in the record, to support his views. These writings, however, indicate that the matter is still an unresolved medical problem. In the expert’s own experience in about one per cent of the cases observed by him, there was a possibility, but no more than that, that bacterial infection was a contributing cause.
The evidence taken at its best for the dependents does not go beyond showing a possible cause. It comes down to this: There is some basis for the hypothesis that staphylococcus infection is a cause of leukemia, but so far it is only an unproved hypothesis, which the dependents’ expert thinks may sometime be proved. This is not proof of cause. Cases are to be distinguished where the expert opinion is that a medically accepted cause was operative to relate the accident to the injury.
Sheppard’s Case,
We think that upon the entire evidence the dependents
*754
have failed to sustain the burden of proof in attempting to prove the cause of the disease, where the cause is admittedly unknown, by proof of a particular cause. It follows that the decree must be reversed.
Falco’s Case,
bo ordered.
Notes
The board apparently interpreted this answer in the affirmative as meaning that leukemia was caused by the infection and not, as the self insurer contends, as meaning that it was speculative whether the leukemia was caused by the infection.
Ralph’s Case appears to be based primarily on the ground that the expert’s opinion was equivocal.
The “cause of leukemia as one agent causing one disease is unknown. However, many conditions being described seem to be outstanding in the history of patients who have come to develop leukemia; among them are chemicals, drugs, traumatic infection, both bacteria and due to viruses. . . . As to infection, especially virus, there is a tremendous body of evidence that transmission of virus may in fact be responsible .... [A]t least in animal leukemia you have very good evidence for the viral theory.”
