TRANSACTIONS OF SECTION D. 527 
TUESDAY, SEPTEMBER 16. 
The following Papers were read :— 
1. Living Cultures of the Embryonic Heart shown by the Micro- 
Kinematograph. By Professor H. Braus. 
Harrison’s discovery that individual cells and whole organs of the embryo 
may be isolated and cultivated in a cover-glass—i.e., made to grow outside the 
organism—is now well known. It may, however, be of some interest to see the 
phenomena of growth and movement demonstrated, if not in the actual living 
cultures which I have shown elsewhere,’ at least in the kinematograph. 
Micro-biographs were taken in order to exhibit delicate phenomena of move- 
ment that were too rapid or too slow to be appreciated by simple inspection. 
The beating heart exhibited is that of a frog larva (Hana esculenta) six milli- 
metres long. At this stage the heart is only just perceivable as a tiny dot upon 
a black background ; its pulsation can be recognised only by magnifying it. In 
form it is an S-shaped tube. In the cultures the shape and also the diameter 
of this tube gradually change. 
When the photographs were taken this preparation was seven days old, yet 
the regular rhythm of pulsation is the same as on the first day—viz., about 
eighty beats per minute. 4 
The movement is peristaltic. Pulsation of the sinus, atrium, ventricle and 
bulbus can be clearly distinguished. Under the influence of chemical rays dis- 
turbances (suspension and irregularity) are caused during the exhibit. There 
are also typical ‘refractory ’ periods in certain cases. 
To prove that the preparation is really growing I have photographed some of 
its pigment cells on a larger scale. The micro-biographs were taken at intervals 
of ten minutes, on the average, during a period of ten hours. It takes only a 
few minutes to show them on the screen, so that the movements (increase in 
thickness, amceboid movement of the processes, shifting of the cells in toto) seem 
to take place rapidly. 
The heart has no ganglion cells either at the beginning or at the end of the 
experiment. It consists of two epithelial membranes: the endocardium and an 
exterior layer, the visceral mesoderm. Every cell can be thoroughly inspected 
in control-preparations, and \by a series of sections of hardened cultures. As the 
cells lie in a compact layer, ganglion cells are certainly not present. Nerves 
proper are still a long way off. The vagus has only a short, stumpy Ramus 
intestinalis, which follows the intestine only slightly, but cannot be removed 
with the heart. The sympathicus is at this stage represented by mere traces near 
the aorta, and therefore not present in the preparation. Experiments with glass- 
culture of nerves, however, show that real nerves do not originate, except by 
growth from the central neuroblasts. 
Nor can it be the muscles that conduct the stimulus, for the heart cultivated 
in vitro possesses at first no cross-striping and no muscle cells that are micro- 
scopically distinguishable. Yet there is conveyance of stimulus beyond doubt, 
as seen in the disturbances of co-ordination—e.g., in a ‘refractory’ period. The 
plasmoderms, therefore, the protoplasmatic links between the cells, must be the 
conductors of the stimulus. 
2. The Scottish Zoological Park. By Dr. W. S. Brucs, F.R.S.E. 
3. Joint Meeting with Sections I and K. 
Synthesis of Organic Matter by Sunlight in Presence of Inorganic 
Colloids, and its Relationship to the Origin of Life. By Professor 
Bensamin Moors, F'.R.S., and ARTHUR WEBSTER. 
The whole world of living plants and animals depends for its present con- 
tinuance upon the synthesis of organic compounds from inorganic by the green 
* Naturwiss. Mediz. Verein, Heidelberg, July 11, 1911 (Miinchener Mediz. 
Wochenschrift). 
