244 A. T. CAMERON 



was present in one other gland apparently, but not definitely non- 

 strumous, a'nd Morgenstern concluded that it is probably only present in 

 pathological (strumous) tissue. The extremes found were 0.006 and 

 0.009 per cent (mean 0.008). Excluding the 22 pathological thyroids, 

 analysis of Morgenstern' s figures shows the following average percentages 

 (the extreme figures are given in brackets) : Ca, 0.4 (0.09 1.3) ; S, 0.2 

 (0.040.65); P, 0.19 (0.081.2); Cl, 0.25 (0.130.45); I, 0.013 

 (not found in 8 cases; maximum observed 0.054). All these results were 

 for fresh tissue. 



The phosphorus content of the thyroid has been exhaustively examined 

 by Fenger (&) (1913-15). Tor beef thyroids the variations are 0.6 to 0.8 

 per cent (fetuses), 0.4 to 0.9 per cent (adults), for dry tissue. The aver- 

 age content for nearly 4,000 beef thyroids was 0.4 per cent, dry tissue, or 

 0.12 per cent, fresh glands. The dried glands from male human fetuses 

 contain 0.72 per cent; from female, 0.79. 



Normal human thyroids have an average silicon content of 0.0082 per 

 cent (Schulz). Gautier found arsenic in thyroid (0.00005 to 0.0009 per 

 cent, fresh tissue) . Its presence is denied by Hodlmoser. 



Labat (1913) found bromin present in 16 of 24 human thyroids exam- 

 ined, in amounts varying from 0.00007 to 0.003 per cent for fresh tissue. 

 Baldi (1898) had found 0.035 per cent, but his method probably lacked 

 accuracy. 



Gautier and Clausmann (1913) found in fresh human thyroid 0.00054 

 per cent of fluorin, and in sheep's thyroid 0.00046 per cent (dry tissue: 

 0.00212 and 0.00162 per cent). 



Macadam (1854) having demonstrated that iodin was present in a 

 number of edible plants, concluded that it should be present in the higher 

 mammals, including man, but was unable to detect it. Kocher (c) (1895) 

 suggested that since both thyroid extract and iodin have a beneficial effect 

 on cachexia thyropriva, iodin might be a constituent of the gland. At his 

 suggestion Tschirsch tested the gland for iodin, iodides, and iodates, with 

 negative results. Almost immediately afterwards, Baumann (#)(&)(! 89 5) 

 announced his discovery of iodin in thyroid tissue. He found it invariably 

 present in sheep and human glands, and to a less extent in goitrous glands 

 and in hog thyroids. Subsequently (1896) from data for a large number 

 of human glands he obtained the extremes : a trace to 0.46 per cent iodin 

 in dried tissue, the average content being 0.09 per cent. He found iodin 

 absent from the thyroids of many children, and usually present to a 

 smaller degree. The thyroids of dogs, horses, cattle, swine, and rabbits 

 all contained iodin. 



Many researches have since been devoted to the confirmation and exten- 

 sion of these results of Baumann. Much of the work has been vitiated to 

 some extent by the absence until recently of reliable chemical methods for 

 the detection of small quantities of iodin in the presence of organic matter. 



