At the brain autopsy, JFKs brain weighed 1500g. A big man like JFKs brain could have been expected to weight about that. However considering up to a third of JFKs brain was missing, then his brain should only have weighted 1200g at most. Here is a good analysis of this:
1500 g. This was the weight of President Kennedy’s brain during the pathological examination made at the Bethesda Naval Hospital on December 6, 1963 [1]. The brain weight figure allows to infer on the weight of President’s brain at the time of autopsy. Unfortunately, the Bethesda pathologists did not weigh President’s brain during the autopsy in spite of this procedure being a routine part of every autopsy [2].
A three week formalin fixation has been shown to increase the brain weight by 50 g on average [3]. More recent data suggest a variable percent increases in brain weights due to the formalin fixation with an average weight increase of 8.8% over the period of few weeks [4]. If we apply the swelling factor of 8.8%, the estimated weight of President Kennedy’s brain at the time of autopsy was 1373 g.
This figure appears to be too large relative to the amount of damage to the President Kennedy’s brain. The damage to the right hemisphere and the associated loss of brain tissue has been estimated by Mr. David Lifton to be as much as 70% in the right hemisphere [5]. If a normal brain would suffer such loss of tissue, it could not weigh 1373 g. To provide some approximation of the weight of intact and injured Kennedy’s brain, normative data obtained in large cohorts of people can be used. The study by Debakan et al. (1978) [6] analysed the post-mortem brain weights in 2773 males and 1963 females in 23 age categories. The mean weight of a male brain in the age range of 40-50 years was 1430 g (standard deviation 20 g). As President Kennedy was tall (72.5 inches, 184 cm), and since brain weight correlates with body height and weight [6], it is reasonable to estimate that the weight of Kennedy’s brain would be in the upper range of the normal distribution of brain weights in his age category. The upper weight value corresponding to the top 5% brain weights for males aged 40-50 years, estimated using the Z-scores method, would be 1496.2 g (rounded to 1496 g). If Kennedy’s brain sustained a loss of 70% of brain tissue in one hemisphere [5], his brain at the time of autopsy weighed only 972 g. However, even if we accept a smaller than 70% loss of brain tissue of 50% in one hemisphere, the brain weight at the time of autopsy would be only 1122 g. After correcting these brain weight estimates for swelling due to immersing the brain into a formalin solution, Kennedy’s brain during the pathological examination on December 6 was expected to weigh 1058 g or 1221 g for a 70% and 50% loss of tissue in one hemisphere, respectively.SOURCE:
https://thejfktruthmatters.wordpress.com/2016/03/04/1500-g/HOWEVER James Jenkins (3rd class Corpman at Bethesda) says 1500g would be about right if JFKs brain didn't reach proper equilibrium during the fixation process. The following is taken from his book "On The Cold Shoulder Of History":
Mystery solved? Quiet possibly.