In Tanenbaum v. Industrial Acc. Com. (1935) 4 Cal.2d 615, the court said: "It is now definitely settled that the acceleration, aggravation or 'lighting up' of a preexisting disease is an injury in the occupation causing the same. The underlying theory is that the employer takes the employee subject to his condition when he enters the employment, and that therefore compensation is not to be denied merely because the workman's physical condition was such as to cause him to suffer a disability from an injury which ordinarily, given a stronger and healthier constitution, would have caused little or no inconvenience. In such cases full compensation for the entire disability suffered is recoverable although the physical condition of the employee contributed to and increased the disability caused by the injury or prolonged and interfered with healing and recovery. In other words, there is no authority for prorating the extent of the disability due to the accident itself on the one hand and that due to the aggravation caused by the employee's physical condition on the other. " (4 Cal.2d at pp. 617-618.)