72 CIRCULATION OF THE BLOOD 



opposite directions can be seen, making the circulation 

 of the blood quite evident. The same may be seen even 

 better in the mesentery. ..." 



" With unaided vision [and without the help of a 

 microscope] I might have believed that the blood escaped 

 into an empty space and was re-collected again by a 

 gaping vessel, but for the tortuous and scattered move- 

 ment of the blood in different directions and its union 

 again into a definite vessel. . . . Such is the branching 

 character of these vessels as they proceed on the one side 

 from the artery and [are gathered] again on the other 

 side to the vein . . . that there appears to be a network 

 made up of the continuations of the two vessels. . . . 

 Hence it appears to the senses that the scattered blood 

 flows along tortuous vessels, and is not poured out 

 into spaces, but always continues in tubules, and that 

 its dispersion is due to the multiple winding of the 

 vessels" (Plate VIII. Fig. i). 



A few years later Malpighi made a further important 

 observation, the nature of which he failed to interpret 

 adequately. Till his time and beyond, the colour of the 

 blood was believed to be diffused through its substance. 

 We now know that it is concentrated in the so-called 

 red corpuscles, the minuteness of which gives the sus- 

 pension for such it is the appearance of being a uni- 

 form red fluid. Malpighi caught a sight of these particles 

 through his lenses, but he misinterpreted them. In 

 examining a hedgehog he tells us that in a blood-vessel 

 of the omentum ' I saw globules of fat, of a definite 

 outline and red colour. They were like a chaplet of red 

 coral." These globules were the red corpuscles, and in 

 the " chaplet " they were collecting together in rouleaux 

 as they are very liable to do. 



Similar observation of blood corpuscles had been made 

 by several of Malpighi's contemporaries. Thus in 1658 



