THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. XV. DECEMBER, 1894. No. 12. 



Haematoblasts and Blood Platelets, 



By dr. M. L. HOIvBROOK, 



NEW YORK. 



[Read before the American Society of Microscopists in Brooklyn, N. Y., 



August 1894. 



Although a large number of studies and publications 

 hare been made during the last 20 years, on the morpho- 

 logical elements of the blood, we have not yet reached a 

 thorough understanding of the significance of certain 

 form-elements known as the so-called "third corpus- 

 cles." In my studies of the human blood, extending over 

 several years, I have reached some conclusions which I 

 wish to lay before this society. The reasons why great 

 discrepancy of opinion on certain points prevails among 

 observers are two fold. First the structure of the red 

 blood corpuscles is not agreed upon by the majority of mi- 

 croscopists ; second, under the term — " third element" 

 both haematoblasts and blood platelets have been in- 

 cluded by most authors who have written on the subject. 

 I have in the last two years laid before you observations 

 which I think go far to prove the correctness of Elsberg's 

 assertions made in 1879, that the structure of the red 

 blood corpuscle is reticular, the same as that of the col- 

 orless blood corpuscles, the difference being, that in the 

 former, the meshes of the recticulum are filled with a 

 chemically complicated structure, generally termed 

 haemoglobin, whereas, in the latter, the meshes hold a 

 colorless nitrogenous liquid, the " parablast" of French 

 microscopists. It seems to me that no understanding of 



