Found the following hamletworks.org entries referring to line 3580

View Immaterial Textual Note for 3578, etc.
3578 <The interim's mine, and a mans life's no more> 5.2.73
3579 <Then to say one: but I am very sorry good Horatio,>  
3580 <That to Laertes I forgot my selfe;> 3580 

View Commentary Note for 3578, etc.
3578 <The interim's mine, and a mans life's no more> 5.2.73
3579 <Then to say one: but I am very sorry good Horatio,>  
3580 <That to Laertes I forgot my selfe;> 3580 

View Material Textual Note for 3578, etc.
3578 <The interim's mine, and a mans life's no more> 5.2.73
3579 <Then to say one: but I am very sorry good Horatio,>  
3580 <That to Laertes I forgot my selfe;> 3580