Accidental Carbon Monoxide Poisoning

recorded by me at the time, but never used. I have Dr. Beattie's sanction in now bringing them forward. The thymus was weighed and briefly inspected in 113 cases. Thirty-nine were of body weight 15-5{ lb. (0.7-2.6 kg.), and 74 around term-6-11 lb. (2.7-5 kg.), average 75 lb. (3.2 kg.). In these 74 (42 males, 32 females) the average weight of the thymus was 10.5 g. Friedleben' gave 14.3 g. for the same period of life, the lowest figure I have found cited in the literature being that of Sappey,2 3 g. The great diversity of findings for the thymus may very probably be explained by two curious features, the weight spread and the weight range. With regard to the first, there was in the present series little sign of the clustering about the arithmetical mean which biological material so commonly shows. Reading the following figures as " numbers of glands of not more than 3 g. , over 3 but not more than 4 g. ," and so on to the end, they were: 2, 2, 3, 7, 5, 4, 8, 2, 6, 7, 6, 5, 7, 3, 2, 3, 1, 1. The second feature, the weight range, is sufficiently declared by these figures: the actual extremes here were 3-21.5. A mass range of this order for a maturely functioning organ under like conditions is, so far as I know, quite without parallel, and invites comparison with the variability of some vestigial structures. Among the 113, light and heavy glands were met with in either sex, and the sex difference observed by Bratton3 was not decided enough to be obvious in a series of this length. Judging from the evidence of the remaining 39 in various foetal stages, thymus growth is positively correlated with general body growth till full term. In these immature subjects, also in those at term, I quite frequently found, as Astley Cooper is stated to have found in the calf and human foetus, " milky fluid " in the glands. The fluidity appeared limited to the medulla, the cell contents, in the few filmed, being almost entirely mononuclear. As mine cannot be an isolated finding, one must suppose that this excess water content will have influenced other post-mortem estimates of the average weight of the thymus at birth. Of the above 74, 69 were examined for fluidity, of which 17 (24.6%O) showed it in more or less marked degree, their average weight being 13.4 g. , as compared with 9.4 g. for the 52 without fluidity, the weight range of the latter being 3-21 g. Mr. Keynes, commenting on Astley Cooper's findings, says " it is notorious that the thymus disintegrates very quickly after death," and testifies from his surgical experience that " the freshly removed hmnan thymus, even in very young children, is almost entirely solid. " From these statements one is led to conclude that he regards the occurrence of fluidity as a post-mortem change, and so I myself assumed at first. However, apart from the fresh condition of most of this material (1-3 days old), in one subject-7' lb. (3.3 kg.)-showing, by exception, commencing putrefactive changes, the thymus (11 g.) showed no fluidity, nor was it present in any of 6 macerated subjects up to term. With the object of testing the point further, I immersed two glands (9.8 and 12.5 g.) which felt solid in physiological saline for 3-4 days, at the end of which time no fluidity was found. I was therefore left in some doubt. If this be a post-mortem change, it is at any rate remarkably inconstant. -I am, etc.,