[ 267 ] 
VI. Researches on Myohcematin and the Histohcemalins. 
By C. A. MacMunn, M.A., M.D , 
Communicated by Professor M. Foster, See. R.S. 
.Received October 19,—Read November 26, 1885. 
[Plates 11, 12,] 
In a short paper read before the Physiological Society'" in 1884 I gave a prelimi¬ 
nary account of a new colouring matter which I had discovered in muscle by means 
of the spectroscope j also of a class of colouring matters found in the tissues and 
organs of invertebrate and vertebrate animals to which the former pigment evidently 
belongs, and which I named histohsematins from their occurrence in the annual 
tissues. The name myohsematin was proposed for the muscle pigment for reasons 
which will he on veil further on. 
© 
Since the publication of that paper I have been engaged in working out the distri¬ 
bution of these pigments in the Animal Kingdom, and have tried to find out their 
relationship to other colouring matters and the changes produced in them by reagents. 
Methods of Investigation. —These colouring matters have been missed by other 
observers owing to their not having adopted the methods of examination used by me. 
The portion of tissue or organ under consideration is examined in a “ compressorium,” 
by means of which any required thickness can be examined ; it is illuminated by a 
strong light condensed upon it by means of a substage achromatic condenser, and is 
examined by a spectrum eye-piece in a binocular microscope. The advantage of using 
a binocular instrument consists in this :—That one of the tubes is used as a finder, 
and in enabling one to see what is furnishing the spectrum. A one-inch objective 
is the most suitable power for this purpose, though sometimes the ^th or ^th 
may be required. The objectives have been shortened and the condenser so arranged 
as to allow of the full illumination of both fields when the ]dh and -|th objectives are 
used. A Swan lamp was sometimes used, sometimes direct sunlight, but in many 
cases a good Argand gas-burner is sufficient. Observations were frequently checked 
(and measurements made in wave-lengths) by bringing the object in the compressorium 
before the slit of a large one-prism chemical spectroscope,! and 1 have latterly 
* Proc. Physiol. Soc., 1884, No. IY., December 13. 
t Although all the following measurements were made with the same instrument, and are, therefore, 
valuable for comparison, inter se, yet, owing to the great difficulty of seeing these bands, they may 
require slight modifications by and by. 
2 M 2 
