Tributes 



difficulties presented by the methods then available for his purpose. 

 For it must be remembered that in 1897, when he began, the accepted 

 method of obtaining the gases from a sample of blood, for analysis, 

 was to pump them off into a vacuum produced by a Topler mercury 

 pump, the evolution of the gases taking place in a vessel having the 

 form of a series of bulbs, to restrain frothing, while its progress was 

 encouraged and its completeness ensured by bathing the vessel mean- 

 while in hot water. For his purpose, Barcroft needed further to store 

 consecutive blood samples, collected during the course of an experi- 

 ment without contact with air, in a series of such vessels, evacuated in 

 advance ; and eventually he had to put each of these in succession, 

 by turning one of a series of taps, into connexion with the pump 

 through an unjointed run of glass tubing. So he arrived at a rather 

 formidable, multiple apparatus, which had to be fused together by the 

 blow-pipe before each experiment and cut into sections afterwards for 

 cleaning. Modern standards, I suspect, might regard this first apparatus 

 of Barcroft, when fully set up, as justifying a good sized room and a 

 well drilled team for its proper manipulation. Barcroft had only a 

 sort of cubicle, for which memory suggests a floor-space not more than 

 eight to ten feet square, cut off from the corner of a room, which was 

 also a highway through the laboratory, by means of a wooden frame- 

 work draped with green baize. Within this tabernacle he had to install, 

 dismantle and clean his apparatus, and eventually to prepare his animal 

 and perform the whole experiment by himself, with such casual help 

 as he could obtain on occasion from an attendant, or, quite frequently, 

 from passing acquaintances whom he could entice into his service. 

 This procedure was facilitated by the fact that the working space was 

 shut off only by curtains, through which J. B. could put out his head 

 and call anybody in sight to assist him, without leaving hold of what- 

 ever his hands were manipulating. I remember being caught thus 

 myself when dressed for a lawn-tennis party, and having my only pair 

 of clean white trousers bespattered with blood. Such conditions may 

 well have delayed progress and it is hardly surprising that, though 

 Barcroft was all the time steadily at work, and characteristically ready 

 to demonstrate the progress he was making with his method, and the 

 difficulties he v/as encountering and overcoming, to every meeting at 

 Cambridge of the Physiological Society, or to the International Con- 

 gress there in 1898, it was not until he had been at it for about three 

 years that he published the first detailed account of his method. And 

 yet another year was necessary before he had obtained satisfactory 

 determinations of the oxygen and carbon dioxide contents of the 

 arterial blood, and of the venous blood leaving the salivary gland, at 

 rest and in activity caused by chorda stimulation, and had been able 



