Volume 26, Issue 5
November 1947, pages 173-217
pp 173-173 November 1947 Erratum
pp 175-175 November 1947 Erratum
pp 177-194 November 1947
pp 195-204 November 1947
The various parts of the pineal complex,viz., the pineal eye, pineal sac, pineal nerve, dorsal sac, and paraphysis develop in the same way as inSphenodon andLacerta.
The lens of the pineal eye ofCalotes versicolor appears at a later stage of development than inSphenodon andLacerta.
The paraphysis in the embryos ofCalotes versicolor is a simple structure, neither produced into convoluted tubules nor richly supplied with blood vessels.
pp 205-210 November 1947
Human unstriated muscle differs from unstriated muscle of lower animals in the following respects:
The optimum temperature for excitability is higher, 37°.
Many substances affect the tone as well as the excitability to alternating current and potassium similarly. It is suggested that this is due to decrease of adaptation, as an increase produces inhibition.
pp 211-217 November 1947
The properties of the contraction produced by break of a constant current are similar to those of the alternating current off-contracture; the make contraction resembles that produced by alternating current.
The muscle responds to break of a constant current when it may be inexcitable to all other forms of stimulation; it may respond when all the sodium chloride of the saline is replaced with chlorides of lithium, ammonium, potassium, calcium, magnesium and strontium or in acid solutions (pH 5).
Magnesium and adrenaline abolish the break contraction.
The response differs with polarity of the direct current; this suggests that the permeability of the membranes is different in the two directions. Stimulation by alternating current is probably due, therefore, to rectification.
The make and the break contractions bear a reciprocal relation to each other.
With polar stimulation, the results are very complicated; contraction or inhibition may occur at the anode or the cathode on make or break of the current.