1886.] 



MICROSCOPICAL JOURNAL. 



183 



formation of the fibrinous network ; 

 the remnants which are seen enclosed 

 bv the threads of fibrin are held there 

 mechanically, and are not an essen- 

 tial part of the reticulum . 



Some writers teach that it is the 

 white corpuscles which give rise to 

 the fibrin of coagulation. Kemp 

 finds no evidence to support this. 

 The fact that the fibrin is formed 

 in the fluid w^here plaques ai'e ab- 

 sent suggests that the plaques may 

 not be the cause of coagulation. The 

 fact that fibrin is nearly always de- 

 posited moi'e thickly around the 

 granular masses, and even radiating 

 from them, is interesting and sugges- 

 tive, but not conclusive proof that 

 the plaques give rise to them. The 

 same adhesive property of the 

 plaques which makes them adhere 

 to each other may cause the threads 

 of fibrin to adhere to them as fast as 

 they separate from the medium around 

 them. The fact that fibrin is depos- 

 ited most thickly in the vicinity of 

 the plaques may be due to something 

 given up by the plaques which pro- 

 duces or hastens coagulation, and that 

 in dilute solutions this substance is 

 more plentiful in the neighborhood 

 of the granular masses than else- 

 where. Kemp thinks that it is plain 

 that, though there is no histological 

 connection between the plaques and 

 fibrin, there is a chemical one, the 

 plaques, as they break down, giving 

 up something to the plasma, since 

 conditions which retard the breaking 

 down of the plaques also retard the 

 formation of fibrin to precisely the 

 same extent^ while reagents, which 

 preserve the plaques, prevent the 

 format io)i of fibrin altogether . 



The fact that well-preserved 

 plaques are found inclosed in fibrin 

 taken from the heart some time after 

 death cannot be regarded as conclu- 

 sive proof that the plaques are not 

 connected with the formation of clot, 

 unless we could "know positively what 

 they yielded to the clot, and that all 

 were well preserved. 



From all at present known on the 



subject it would seem that ^ferment 

 would be most liable to conduct itself 

 so as to produce these effects. 



Dr. Kemp's conclusions, bi'iefly 

 stated then, are : — 



1. The blood contains a third his- 

 tological element, the plaques. 



2. No evidence that this \'& ge?ieti- 

 cally related to either the white or the 

 red corpusc4e. 



3 Plaques break down at once 

 when the blood is drawn ; other 

 elements do not. 



4. Their breaking do^vn intimately 

 connected in time at least with clot- 

 ting of the blood. 



5. The connection between the 

 plaque and the clot not a histo- 

 logical but a chemical one. 



6. The active agent is most prob- 

 ably fibrin-ferment. 



7. Fibrin is deposited histologi- 

 cally independent of any cellular 

 elements of the blood. 



8. When the clot is scant, fibrin 

 is deposited as thin needle-shaped 

 crystals. 



Life on a Coral Island.* 



BY PROF. W. K. BROOKS. 



After the discovery of the Bahama 

 Islands Columbus writes to Qixeen 

 Isabella that ' this country as far 

 surpasses all otlier lands in beauty as 

 the day exceeds the night in bril- 

 liancy,' and as the scientific expedi- 

 tion of the lohns Hopkins University 

 approached these islands, and the 

 beauties of the land and sea and sky 

 of the tropics began to unfold them- 

 selves before our eyes, all the mem- 

 bers of our party echoed, in words 

 of their own, the impression of the 

 great explorer. 



This island, Abaco, which lies nearly 

 north and south, is about a hundred 

 miles long, and its eastern edge is bor- 

 dered by a narrow sound from three to 

 five miles wide, the outer shore of 

 which is formed by a rim made up of 



* Extracts from the letter of Dr. Brooks in the Bal- 

 timore Sun, Aug. 16, '86. 



