LATER INVESTIGATIONS 15 
In 1885 Speck made another series of experiments, using a form of ergom- 
eter in which a wheel was turned by the hand, the friction being adjusted 
by means of a screw. In these experiments, which were but 2 to 3 minutes 
in length, both the carbon-dioxide production and the oxygen consumption 
were determined. 
Speck's results were published in a number of papers, but were later col- 
lected by him into one volume. 3 His results have also been given in abstract 
by Sonden and Tigerstedt b with special reference to the carbon-dioxide 
production. Speck noticed distinctly the after-effect of work, and it is obvious 
that his experiments at work are vitiated by the fact that since they lasted 
but 2 or 3 minutes, the carbon dioxide excreted during the first part of the 
experiment was unquestionably not so great as would result from the amount 
of work carried out during that period. 
Employing a unique form of respiration apparatus, Hanriot and Richet 
made a number of experiments in 1887, c in which the work was performed 
either by turning a wheel or raising a weight. Their respiration apparatus, 
although extraordinarily ingenious, had practical disadvantages which have 
deterred physiologists as a whole from employing it. In fact, many of the 
experiments reported by these investigators have been the subject of severe 
criticism. 
The effect on the excretion of carbon dioxide of the muscular activity 
of climbing was studied in Kronecker's laboratory, in August 1888, by Gru- 
ber, d who made experiments in which he climbed a distance of 81.55 meters, 
the last 31 .55 meters being in a tower. Experiments were also made in which a 
15-kilogram weight was carried as a load; the effect of practice was likewise 
studied. The carbon dioxide was determined by absorption with soda-lime, 
the kilogrammeters of work performed being computed from the body- 
weight and the height ascended. 
Schnyder," of Kronecker's laboratory, made further studies on the 
influence of muscular activity, employing for the purpose a peculiar form of 
wheel by means of which large blocks of stone could be lifted by the body- 
weight of the subject. The carbon dioxide was absorbed by soda-lime as in 
Gruber's experiments, and the work performed could be computed, due allow- 
ance being made for the friction of the wheel and chain. Experiments were 
also made with an apparatus on the treadmill principle devised by Professor 
Kronecker. 
In addition to the investigations previously cited in which the effect of 
muscular activity upon metabolism was studied, a considerable number 
were carried out by means of special forms of apparatus. These may conven- 
iently be classified according to the method employed into three groups, i. e., 
the investigations of Zuntz and his associates, in which the Zuntz-Geppert 
apparatus was used; the investigations carried out in the French laboratories 
with apparatus devised by Chauveau and Tissot; and investigations in which 
the chamber method was employed, including especially those made by Son- 
den and Tigerstedt, by Rubner, and by Atwater and his associates. 
« Speck, loe. eit., pp. 56-95. 
6 Sonden and Tigerstedt, Skand. Archiv f. Physiol., 1895, 6, p. 1. 
• Hanriot and Richet, Comptes rendus, 1887, 105, p. 76. 
<* Gruber, Ztschr. f. Biol., 1891, M, p. 466. The experiments were reported before the Schweiaerischen Natur- 
forscherveraammlung in Solothurn; a notice with regard to them was also published in October 1888 
in the Correspondenz-Blatte fur Schweiier Aerzte. 
e Schnyder, Zeitsch. f. Biol., 1896, 33, p. 2S9. 
