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were, he thought, striking examples of the illusive effects of illumination, for 

 nothing could be more definite, apparently, than the beaded structures which he 

 produces, and yet they are proved to be perfect illusions. He would say a word 

 relative to the latest observations on the last podura scale, the ordinary black 

 podura. The creature is a distinct species, although the outline of it was pre- 

 cisely the same as the other members of the genus. But whereas they presented 

 colours varying from two to three or more, that to which he referred was of a 

 plain leaden or steel colour. The little clump of hairs seen in profile on other 

 specimens of the podura is never seen in this one. The creature is more active 

 than others of the class, and though the subject had not been thoroughly worked 

 out as yet, the probability was that it would turn out to be a distinct species 

 and very rare. 



Dr. Harkness, at the request of the President, described a mode of exhibiting 

 the circulation of the blood, to which he had drawn the notice of the members 

 that evening. He said at the request of one of the members of the Club he had 

 brought a few frogs for the purpose of illustrating under the microscope the 

 circulation of the blood in the lung. The members were aware that in the family 

 of the Ranse the lung is a sac with rudimentary cells just beneath the pleura 

 The lung being protruded, as it could be readily done by making an incision 

 under the foreleg and through the covering membrane, the pleura, the circula- 

 tion may be maintained for hours if the lung be moistened. He knew of no ex- 

 ample of exhibiting the circulation which was so interesting or so striking as 

 this might be made to be. Under a high power would be seen at a glance (the 

 membrane being very thin), the arterial, venous and capillary circulation. There 

 was also another matter connected with this experiment to which he would call 

 the attention of the Club. The lung being covered with a serous fluid, by drop- 

 ping a pellicle of water upon the lung, it would sometimes be possible to produce 

 the effect of a compound microscope. When moisteniug the lung with a tooth- 

 pick or small glass rod, he had been able to obtain a small globule of water 

 almost spherical, and by bringing the instrument to bear upon that specially 

 he had obtained a magnifying power of 1,000 or 1,500, while using no higher 

 power than the inch object glass, equal to a power of about 100. 



The thanks of the meeting were given to Dr. Harkness. 



Mr. Lowne made a statement with reference to the white blood corpuscles of 

 the newt which he was exhibiting, and said that some very extraordinary phe- 

 nomena might be observed in leucocytes, or white blood corpuscles. He said 

 that although those which he was exhibiting appeared to be dead, yet after 

 resting for a short time they would probably manifest signs of vitality, and ex- 

 hibit the phenomena he was about to describe. The blood had long been known 

 to contain two kinds of corpuscles, white and red. The red are elliptical in 

 shape in most ovipara, as birds, reptiles, and fish, but circular in mammals. 

 The white corpuscle was discoid only when dead ; when it was alive it put 

 forth processes very like the pseudopodia of the amoeba. These blood corpuscles 

 are little masses of living tissue which circulate in the blood, and viewed under 

 favourable circumstances, could be seen adhering to the walls of the vessels, 

 and putting forth the pseudopodia -like processes alluded to. If the blood be 

 taken from the vessels and observed under its natural conditions, those processes 

 would still be seen to be put forth. If our own blood be taken it would be 

 necessary to exercise care to keep the temperature very accurately up to 

 the ordinary temperature of the body, as a little deviation from it would prevent 

 the movement of the leucocytes, but if the blood be taken from cold-blooded 



