188 



THE AMERICAN MONTHLY 



[October, 



of the organs denominated hearts by 

 Baron, Cuvier, and Prof. Owen, all 

 subsequent writers on the subject. 



' These so-called hearts seemed to 

 me very unlike any moUuscan heart 

 that had ever come under my obser- 

 vation, and on attentive examination 

 it became evident that they give ofl^ 

 no arteries, as they had been described 

 to do ; and, moreover, that their 

 apices, from which the arteries were 

 stated to pass oft', appeared to open 

 externally. For these and other rea- 

 sons I was inclined to disbelieve in 

 their cai'diac nature, and to regard 

 them rather as oviducts.' 



Hancock also discovered the true 

 hearts, situated above the stomach, 

 and two secondary pulsatile vesicles, 

 situated somewhat posteriorly to the 

 true heart. 



These hearts, oviducts, or segmen- 

 tal organs (as they were called by 

 Prof. E. S. Morse, who compared 

 them to the segmental organs of an- 

 nelids) are generally described as 

 having two openings — one a small 

 one extei'nally, and another, large and 

 funnel-shaped, opening in the perivis- 

 ceral cavity. 



I have brought with me a series of 

 sections, by means of which I hope 

 to show you that, although the open- 

 ing to the exterior is very clear and 

 manifest, the internal opening is not 

 of so simple a nature as has hitherto 

 been described. I find that the inter- 

 nal end is in very close relation and 

 probable direct communication with 

 the interior of a convoluted tubule or 

 glandular sort of vesicle. These ves- 

 icles, two in number, are found on 

 the looped portion of the alimentary 

 canal, and, so far as I am aware, and 

 from what I have been able to gather 

 from some of the plates accompany- 

 ing the article by Mr. Albany Han- 

 cock, above referred to, correspond 

 somewhat in situation to his pulsatile, 

 secondary vesicles. On closer exami- 

 nation a communication was found to 

 exist between these pulsatile vesicles 

 and one of the diverticula of the ali- 

 mentary canal, so that we have here 



an indirect communication between 

 these oviducts and the lower portion 

 of the alimentary canal. Until fur- 

 ther and more extensive studies shall 

 have been made on other brachiopods 

 I shall abstain from entering into a 

 discussion on the morphological sig- 

 nificance of these findings. The speci- 

 mens which I have brought with me 

 to-day will, I hope, be sufficiently 

 convincing, at least so far as lingula 

 is concerned. I shall present a more 

 detailed account of the histology of 

 lingula at some future nor very dis- 

 tant day. To-day I am obliged to 

 limit myself to this brief and frag-- 

 mentary account. 



Upon a Microscopical Method 



of Studying the Ampliib- 



ian Brain.* 



BY HENRY F. OSBORNE. 



The brain is hardened in bichro- 

 mate of potash (Miiller's fluid) the 

 ventricles being fully injected. After 

 the usual alcohol treatment, the brain 

 is placed for one week in carmine 

 solution ; then for 24 hours in acetic 

 acid. 



The imbedding mass is prepared 

 by shaking the contents of an egg 

 with three drops of glycerin. After 

 soaking in this mass the brain is 

 placed in position, and hardened in 

 the vapor of boiling alcohol spirit, 

 80 per cent. The mass is then placed 

 one week in absolute alcohol. 



The cutting is done with Jung's 

 microtome ; 50 or 60 sections collect- 

 ing on the razor in alcohol are then 

 floated at once, in order, upon the 

 slide. To keep them in place they 

 are covered with thin blotting-paper 

 during alcohol and oil of cloves treat- 

 ment. This is removed and the sec- 

 tions mounted in the usual way. 



The section glasses, and then the 

 sections showing particular struc- 

 tures, are then indexed. 



* Abstract. Read before Section G, A. A. A. S. 



