68 



SCIENCE-GOSSIP. 



BLOOD AS A MICROSCOPE OBJECT. 

 By Dr. Alfred C. Stokes. 



:.' HAVE recently been examining, with great 

 satisfaction, a mount of an object so common 

 that every human being carries it about with him 

 from even before the day of his birth to the 

 moment of his death, and for some time after. He 

 is unable conveniently to do otherwise. The 

 object can therefore be obtained at any moment, 

 and as its preparation calls for no preliminary 

 treatment, this adds somewhat to its interest. 

 The only objection is that age is a necessity 

 for one- structural feature, and for only one ; the 

 older the mount the better. Still for the purposes 

 of this paper, a recently prepared slide will answer 

 all the requirements. 



The object is nothing more than a small drop of 

 human blood mounted in its natural state and 

 allowed to ripen, if so disrespectful an expression 

 be allowable. The drop of blood must be left to dry 

 under the cover and protected from the external 

 air by the ring of cement. Prick the finger-tip, 

 quickly touch with the drop a thin cover-glass ; as 

 quickly invert the blood over an exceedingly thin 

 cell, or over a slip without a cell, so that capillary 

 attraction shall spread out as thin a stratum of the 

 liquid as may be, and, if possible, with but a single 

 layer of red corpuscles. The cover is then to be 

 rapidly cemented down, and the preparation left to 

 itself for an hour or two, or for a shorter time. 

 The entire mass of fibrin in the drop will coagulate, 

 thus forming the object sought and which may be 

 made so useful to the amateur microscopist, so 

 instructive and attractive. It is best to use a drop 

 so small or a cover so large that the capillary 

 wave may become quiet and the material exhausted 

 before the margin of the cell be reached. 



If this preparation be allowed to remain in the 

 darkness of the cabinet for a year, the red corpuscles 

 will be gradually bleached and the reticulated 

 structure of their protoplasm become superbly 

 distinct and convincingly apparent, while the 

 microscopist will have the satisfaction of knowing 

 that no re-agent but time has touched the discs. 

 With a good one-fifth inch objective, or with a 

 higher power, these minute reticulations become 

 defined in such a way that there can be no doubt 

 as to their existence, but whether or not the net- 

 work becomes visible by reason of the spontaneous 

 bleaching, or of the more than probable changes 

 that must take place as the dessication advances, 

 I do not presume to say. But since the reticula- 

 tions in the red corpuscles become more distinct, 

 and apparently more numerous, as the preparation 

 grows older, a little scepticism is not unnatural. 

 However, the protoplasmic network can thus be 



seen, whether the observer accepts or rejects the 

 teaching that it is normal structure. 



It is to the threads of coagulated fibrin that the 

 microscopist is asked to look, with particular 

 reference to the use of the object as a means for 

 studying the adjustment of his objective. There 

 is some reason to believe that, in this country at 

 least, some amateur microscopists, some too that 

 should know better, fail to study the effect of the 

 collar-adjustment as it should be studied. Some 

 of them either neglect it almost entirely, giving the 

 collar a shove from time to time, and being content 

 with that, or not giving it even so much attention, 

 but setting it at any point which maybe convenient 

 and leaving it there. Another class is no less 

 common, whose members use non - adjustable 

 objectives with covers of improper thickness. 

 What the British amateur does in this respect 

 I have no means of knowing, but I have had some 

 amusing experiences with the amateur in the 

 United States of America. One man of whom I 

 have heard, but in whose existence I refuse to 

 believe, is said never to use covers less than one- 

 fiftieth inch thick, because, as he can only afford 

 cheap, non-adjustable objectives, he is unwilling 

 that others more fortunate shall have the satis- 

 faction of examining his preparations under better 

 conditions than he can possess. I have searched 

 my new dictionary in vain for a word to describe 

 that man. Another man-like biped, whom I know 

 existed at one time, and who claimed to be a 

 microscopist, said, in reference to the adjustment- 

 collar, " I don't know what that thing is, and any- 

 way I don't know what it is loose for." 



If the reader's blood is anything like mine, the 

 fibrin in the mounted capillary film will coagulate 

 in fine threads connecting every red corpuscle with 

 every other ; it will form clusters of filaments, 

 isolated or aggregated into irregular skeins and 

 flattened masses ; it will produce minute figures 

 like the delicate weaving of fairy spiders, or 

 microscopic work from the looms of the elves. 

 Disintegrated white corpuscles will be scattered 

 about the slide in islands of colourless shreds and 

 fragments, around which the fibrin will form its 

 filamentous figures, and so unite the entire 

 preparation into one reticulated entity. 



Within the larger meshes, and sometimes under 

 a different focus, can be seen a fibrinous network 

 so minute that an eighth or tenth-inch objective is 

 needed to display it distinctly, and even then the 

 meshes are indescribably small, they are truly 

 microscopic. It seems that not only does all the 

 fibrin ccagulate into a reticulation, but that the 



