[nicholls] significance OF "DUST-BODIES" OF THE BLOOD 5 



could not make out with certainty that the granules were actually ex- 

 truded from the leucocytes, although they were under the impression 

 that this was so, nor could they convince themselves that there was any 

 destruction of the leucocytic granulations. In hardened preparation 

 large and small granulations stained with eosin. They concluded that 

 the free bodies of the blood are extruded leucocytic granulations. Their 

 views as to the bearing of this on immunity will be referred to later. 

 Since the publication of these studies, a few isolated references have 

 been made to the subject, but have added little or nothing to our know- 

 ledge. 



The very careful and painstaking investigations of Stokes and Wege- 

 farth tended on the whole to confirm in many points the observations 

 of Millier, but have been far from clearing up all the difficulties which 

 beset the subject, and their conclusions, while in the highest degree 

 suggestive and stimulating, could not, in my opinion, be accepted until 

 further light was forthcoming. 



This subject of the " Dust-bodies " of the blood has been of con- 

 siderable interest to me since I first saw them, and has occupied my 

 attention at various times during the past few years. In a brief com- 

 munication, entitled " Preliminary N"ote on the so-called ' Dust-bodies ' 

 of the Blood" (Philadelphia Medical Journal, p. 387, 1898), basing 

 my opinion on the staining properties of the " Dust-bodies " when fresh 

 blood was treated with solutions of eosin, and the behaviour of the 

 leucocytes under prolonged observation, I was led to the conclusion that 

 the bodies were derived from the leucocytes and were, in fact, extruded 

 granulations. Subsequent study has, however, convinced me that, while 

 these observations were correct in so far as they went, they did not 

 represent the whole truth. The present communication, therefore, is 

 the outcome of much more extended investigation, and will I hope, tend 

 to elucidate still farther a somewhat obscure and difficult subject. 



For the purposes of this research, freshly-drawm blood was em- 

 ployed, taken from a considerable number of persons, both in a state 

 of health and disease; also, the blood after death, various exudates and 

 transudates, the cerebrospinal fluid, and the lymph found normally in 

 small amounts in the serous cavities. The blood of rabbits, guinea- 

 pigs, cats, dogs, and frogs, was also studied. It was found impossible 

 to draw any accurate conclusions from hardened films prepared by 

 streaking, since, even with the greatest care, one cannot avoid destroying 

 certain of the blood cells, and thus introducing an extraneous element 

 into the calculation. 



The technique employed is as follows: The blood is drawn from 

 the lobe of the ear, or the end of the finger, the part being first cleansed 

 with water and subsequently with ether. The first drop of blood is 



