THE THYMUS GLAND AND THE ADRENALS. 177 



With lecithin, sometimes termed "phosphorized fat/ 7 which 

 represents about one-tenth of the solids, the case is different, 

 since its formula (C 44 H 90 NP0 9 ) suggests that phosphorus may 

 represent the constituent we are seeking. It is not only a 

 prominent component of the whole cerebro-spinal and nervous 

 systems, however, but it is also a constituent of the red and 

 white corpuscles, milk, bile, serum, semen, and pus. Another 

 body, protagon (C 160 H 308 N 5 P0 35 ), has also been isolated from 

 brain-substance by Liebreich, who considered it as the main 

 cerebral constituent: an opinion sustained by Gamgee and 

 Blankenhorn. 67 Hoppe-Seyler and other investigators are, 

 however, inclined to consider it as a mixture of lecithin and 

 cerebrin. Whether this be the case or not, phosphorus again 

 appears as the only element capable of being at all associated 

 with the question in point. 



To merely adopt phosphorus as the characteristic con- 

 stituent of the thymus gland, however, and declare that it is 

 through its minus or plus production that the mental attributes 

 of children are developed, would merely constitute a theory. 

 As a stronger position is desired for all the deductions vouch- 

 safed in this work, collateral evidence must be sought. 



The observations of Cabot, that, while thyroid extract 

 stimulates growth, it fails to enhance mental development in 

 idiots other than myxcadematous ones, raises the question as 

 to whether such results can be due to the absence of phos- 

 phorus in the thyroid. If such is the case, the absence of this 

 element should also show itself in the results obtained from 

 the extract in some other disease, if any structure other than 

 the brain and nervous system, in which a morbid deficiency 

 of phosphorus also exists, is a feature of that disease. We 

 know, for example, that phosphorus is introduced into the 

 organism with food, and that calcium phosphate, by becoming 

 deposited in the bones, gives them their hardness. Is there 

 any evidence that the bones of subjects in which thyroid ex- 

 tract is successfully administered lack of this hardening con- 

 stituent? Referring to the use of thyroid extract in cretinism, 

 T. Telford-Smith 58 makes the following statement: "I have 



67 Gamgee and Blankenhorn: Journal of Physiology, vol. ii, 1879. 



68 T. Telford-Smith: Lancet, Oct. 2, 1897. 



