1864] . On a New Mercurial Gasometei' and Air-pump, 321 



earlier than other muscular tissue. The relation which the amyloid sub- 

 stance bears to it is therefore of much interest. In all embryos, without 

 exception, which I have had an opportunity of examining at a time when 

 they were closely approaching the period of birth, theYe has been no more 

 than a trace of amyloid substance remaining in the muscular structure of 

 the heart. The preceding Table, drawn up from examination of the heart 

 of the embryo of the sheep, closely represents the corresponding state in 

 other embryos. 



The liver, which is the organ destined to form the amyloid matter during 

 adult Ufe, naturally has an increase of this material going on in its tissue 

 up to and after birth : it does not make its appearance in the liver until 

 the embryo is already well advanced in development ; it then is found 

 gradually and very slowly to increase in amount, but even at the time of 

 birth is present in comparatively small quantity (2 per cent, in the liver of 

 a lamb 20 inches long). 



The rapidly growing horn of a young stag was not found to contain any 

 amyloid substance in the tissues, neither does it exist in the texture of the 

 growing horn of the calf ; it is not found in the hair-bulbs of the adult, 

 neither is it to be discovered as a formative material of the newly formed 

 muscular fibres of the uterus when this organ is undergoing its remarkable 

 reconstruction after delivery. 



What is the function of this material during foetal life ? It can at least 

 be said it does not change into sugar, neither does it give rise to fat. It 

 seems to be a formative material, which, gradually becoming united with 

 nitrogen, gives origin to the azotized structures. 



IX. "Description of a New Mercurial Gasometer and Air-pump." 

 By T. R. Robinson, D.D., LL.D., F.R.S., &c. Received June 2, 

 1864. 



In some experiments on the electric spectra of metal and gases, I felt 

 the want of a mercurial gasometer for working with such of the latter as 

 are absorbable by water. That of Pepys is on too large a scale for my re- 

 quirements, and it seemed better to contrive one more easily manageable, 

 which I saw could also be made to act as a mercurial air-pump. In this 

 I have succeeded to my satisfaction ; and I hope that a description of it 

 may be useful to those who are engaged in similar researches. 



There have been several attempts made to exhaust by means of mer- 

 cury, the chief of them with which I am acquainted being those of Close 

 (Nicholson's Journal, 4to, iii. p. 264), Edelcrantz (Nicholson, 8vo, vii. 

 p. 188), Traill and Children (Nicholson, xxi. pp. 63 & 161), and that 

 of Geisler, which he uses in preparing the beautiful vacuum-tubes which 

 bear his name. In all the principle is the same. A vessel is filled with 

 mercury, which is made to descend from it, leaving in it a Torricellian 



