no A 8] EMY ° F SCIENCES] BIOGRAPHY 5 



made the most interesting and ingenious experiments on the matter, by cutting up the muscular 

 disk into strips of various sorts in which contraction waves were trapped and kept going for days. 

 He used his training in chemistry to advantage in many researches. He studied the effect of 

 various solutions on contractions. Thus he found that sodium chloride of the sea water is the 

 chief stimulant to pulsation in Cassiopea, while magnesium is the chief inhibitor. These chem- 

 ical studies became elaborated in the successive years. They led to a new and greatly improved 

 method of stupefying marine animals by means of a pure magnesium solution isotonic with 

 sea water and to a method of stupefying by carbon dioxide. He found that — 



sodium, which is a powerful nervous and muscular stimulant, depresses the movements of the rhythmically 

 beating cilia of troehophore larvce, ctenophores, etc. On the other hand, these cilia beat at an abnormally rapid 

 rate in magnesium. There is thus a converse relation in the effects of these ions upon the activity of these cilia 

 in comparison with their effects upon nerves and muscles, for which sodium is a stimulant and magnesium a 

 depressant. The explanation is that cilia-bearing cells are very sensitive to pressure and when the surface of 

 the body is bathed in sodium a strong muscular contraction results, thus augmenting the pressure upon ciliated 

 cells and stopping them." (A. G. M., MSS.) 



Later, he studied the degree of acidity of the sea water in the zone of the coral reefs. 



His researches, similarly, led him to use his training in physics, as already suggested. 

 While he was assistant in physics at Kansas he began a research which showed that leaves 

 are as efficient as a lampblacked surface in their ability to absorb or to radiate heat, but if 

 dew collects upon the leaf its radiation is reduced, becoming that of a water surface. This 

 research involved the use of a highly sensitive thermopile and a reflecting astatic Thomson 

 galvanometer; he had to devise still other apparatus. In his researches on color in Lepidoptera 

 (which is located on the scales) he showed, by pendulum experiments, that scales are not useful 

 to increase the friction between wings and air. At the Tortugas Dr. T. W. Vaughan, who 

 was studying the growth of corals, needed information on the effects of temperature upon 

 Coelenterates and Mayor made the required studies, which are published in Nos. 40, 41, 44, 

 and 54 of his bibliography. These temperature studies were made, inter alia, on the large 

 medusa, Aurelia aurea, the only Scyphomedusa that extends from pole to pole. At Tortugas, 

 where at the surface the sea is often 29° C, this temperature is an optimum for Aurelia, which 

 suffers if the temperature is appreciably higher or lower than 29°. At Halifax, on the other 

 hand, Aurelia is killed by a temperature of 29°; but it may be frozen with impunity. There 

 is thus a remarkable adjustment of this organism in different climates to the temperature 

 conditions of the various regions. The results of these temperature studies he applied to the 

 problem of coral reefs. It appears then that Mayor's engineering training was of great use 

 to him in the solution of biological problems. It is obvious that he had some of his father's 

 dexterity in physical manipulation. 



Mathematics, Mayor states in his autobiography, was one of the courses at Stevens Insti- 

 tute which attracted him. Accordingly, we find him making much use of it in his researches. 

 He discusses mathematically the degree of retardation of the pendulum if the scales on the 

 wings of Lepidoptera function to increase friction. He discusses mathematically the chances 

 that a given mutation should have occurred independently in the 5 species out of 25 in the 

 genus in which it is found. He finds that the starved jellyfish loses weight in accordance with 

 the formula y = w (1 — a) T , where y is the weight at the end of x days, w is the weight at the 

 beginning of the experiment, and a is a constant less than unity. Again, he shows that the 

 rate of nerve conduction in Cassiopea increases in a direct ratio as the electrical conductivity 

 of the sea water increases between salinities of 18 per cent to 40 per cent in accordance with 

 the formula y = 0.945a; +4.4, where y is the rate of nerve conduction (that in normal sea water 

 being 100), x is the degree of dissociation of the cathions of sodium, potassium, magnesium, 

 and calcium in sea water; that of normal sea water of 36.24 salinity and 8.22 PH being 100. 

 Repeatedly he succeeds in expressing relations between environmental conditions and vital 

 response in a simple formula; he was satisfied with nothing less. In this respect Alfred G. 

 Mayor was like his father, whose law of the relation between the time during which the after 

 sensation of a sound does not appear to diminish in intensity and the number of vibrations 



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