26 CHEMICAL CONSTITUENTS OF BODY AND FOOD. 
Globin prepared from haemoglobin is stated to be free from ash. It is 
perhaps hardly correct to say that the ash is an impurity, because it is 
extremely probable that in their native condition the actual proteid molecules 
are combined more or less loosely with inorganic substances. 
The process of incinerating has its drawbacks in determining the amount 
of ash in a proteid ; for in the heating, some of the sulphur of the proteid, and 
when phosphorus is present the phosphorus also, will be oxidised and form 
sulphuric and phosphoric acids respectively. H. Schulz x has recently shown 
that sulphates are formed in tissues as a result of drying them at 110° C. ; this 
would occur to a greater extent still at the temperature necessary for ignition. 
The sulphur in proteids is in the body normally burnt off as 
sulphuric acid, which leaves the body in the urine as sulphates. The 
ethereal hydrogen sulphates of the urine originate in the intestine, as a 
result of putrefactive changes in proteids, 2 and when putrefaction is 
hindered by the administration of large doses of iodoform in dogs, these 
products do not appear in the urine. 3 Kriiger * has shown that a part 
of the sulphur in proteids is present in a condition of stable combination, 
a part loosely combined ; the latter is removed by boiling with alkalis, 
the former is not; the proportions of the two differ in different proteids. 
Among the primary decomposition products of proteid, thio-acids, of 
which thioglycollic acid is probably the most abundant, are obtained. 5 
From the elementary analyses which have been made of proteids, various 
observers have attempted to construct an empirical formula for certain typical 
proteids, egg-albumin being the one usually selected. Thus Lieberkiilm 
assigned to albumin the formula C 7 . 2 H 11 .,X ls ('). ) .,S ; Loew ° gives the same 
formula ; Harnack ~ gives Co . t H...,.,X- i2 < > 66 S 2 ; Schutzenberger, 8 C. 240 H a , lo N 65 O 75 
S 3 ; and there have been others. The great divergence between these numbers 
requires no comment. 
Equally conflicting results have been obtained in attempts to ascertain the 
molecular weight of albumin. Lieberkiilm, in 1852, attempted to establish it 
by analysing the copper compound of egg-albumin ; more recently, Harnack 
has done similar work. But very little importance can be attached to 
such work at present, for Chittenden and Whitehouse 9 find there is no 
definite copper albuminate, but that there are several in the mixture ; and 
equally variable results are obtained with other metals both with egg albumin 
and myosin. 
Such researches lead to the same conclusion as dialysis, namely, that 
the molecules of proteid are extremely large, but leave us quite in the 
dark as to their exact magnitude. 10 It is possible that in the future the 
1 Arch./. <i. ges. Physiol, Bonn, 1894, Bd. lvi. S. 203. See also Halliburton and Brodie, 
Journ. Physiol., Cambridge and London, 1S94-95, vol. xvii. p. 154. 
- Baumann. Ztschr. f. physiol. Chem., Strassburg, Bd. x. S. 123. 
3 Morax, ibid.,S. 318. See also more recently Nuttall and Thierfelder on "Auimal 
Life without Bacteria in the Alimentary Canal,*' Mi., vol. xxi. p. 109 ; xxii. p. 62. In this 
paper it is shown that healthy animal life is possible without micro-organisms in the 
alimentary canal. 
i Arch.f. J. ties. Physiol., Bonn. 1SSS, Bd. xliii. S. 244. 
5 F. Suter, Ztschr. f. physiol. ''hem., Strassburg, 1895. Bd. xx. S. 564 ; E. Baumann, 
ibid., S. 583, and Virchow's Archie, 1S94, Bd. exxxviii. S. 560 ; E. Salkowski, ibid., S. 562. 
6 Loew and Bokorny, "Die chemische Kraftquelle im lebenden Protoplasma," Munich, 
18S2. 
7 Ztschr. f. physiol. Chem.. Strassburg. Bd. v. S. 207. 
8 Bull. Sue. cltim.. Paris, Sir. 5. tomes xxiii. and xxiv. See also Schmiedeberg, Arch. f. 
ex])er. Path. u. Pharmakol., Leipzig, 1897, Bd. xxxix. S. 1. 
9 Stud. Lab. Physiol. Client.. New Haven, vol. ii. p. 95. 
10 The large size of the proteid molecule can be very strikingly demonstrated by the fact 
