Foam Fixes+Changes

code/modules/mob/living/simple_animal/bot/medbot.dm

@@ -492,7 +492,7 @@
 				if(reagent_id == "internal_beaker")
 					if(use_beaker && reagent_glass && reagent_glass.reagents.total_volume)
 						var/fraction = min(injection_amount/reagent_glass.reagents.total_volume, 1)
-						reagent_glass.reagents.reaction(patient, 2, fraction)
+						reagent_glass.reagents.reaction(patient, INGEST, fraction)
 						reagent_glass.reagents.trans_to(patient, injection_amount) //Inject from beaker instead.
 				else
 					patient.reagents.add_reagent(reagent_id,injection_amount)

code/modules/reagents/Chemistry-Holder.dm

@@ -387,45 +387,48 @@ var/const/INGEST = 2
 			can_process = 1
 	return can_process
 
-/datum/reagents/proc/reaction(var/atom/A, var/method=TOUCH, var/volume_modifier=0)
-
+/datum/reagents/proc/reaction(atom/A, method=TOUCH, volume_modifier = 1)
 	switch(method)
 		if(TOUCH)
 			for(var/datum/reagent/R in reagent_list)
 				if(ismob(A))
-					spawn(0)
-						if(!R) return
-						var/check = reaction_check(A, R)
-						if(!check)
-							continue
-						else
-							R.reaction_mob(A, TOUCH, R.volume+volume_modifier)
+					if(!R)
+						return
+					var/check = reaction_check(A, R)
+					if(!check)
+						continue
+					else
+						R.reaction_mob(A, TOUCH, R.volume*volume_modifier)
 				if(isturf(A))
-					spawn(0)
-						if(!R) return
-						else R.reaction_turf(A, R.volume+volume_modifier)
+					if(!R)
+						return
+					else
+						R.reaction_turf(A, R.volume*volume_modifier)
 				if(isobj(A))
-					spawn(0)
-						if(!R) return
-						else R.reaction_obj(A, R.volume+volume_modifier)
+					if(!R)
+						return
+					else
+						R.reaction_obj(A, R.volume*volume_modifier)
 		if(INGEST)
 			for(var/datum/reagent/R in reagent_list)
 				if(ismob(A) && R)
-					spawn(0)
-						if(!R) return
-						var/check = reaction_check(A, R)
-						if(!check)
-							continue
-						else
-							R.reaction_mob(A, INGEST, R.volume+volume_modifier)
+					if(!R)
+						return
+					var/check = reaction_check(A, R)
+					if(!check)
+						continue
+					else
+						R.reaction_mob(A, INGEST, R.volume*volume_modifier)
 				if(isturf(A) && R)
-					spawn(0)
-						if(!R) return
-						else R.reaction_turf(A, R.volume+volume_modifier)
+					if(!R)
+						return
+					else
+						R.reaction_turf(A, R.volume*volume_modifier)
 				if(isobj(A) && R)
-					spawn(0)
-						if(!R) return
-						else R.reaction_obj(A, R.volume+volume_modifier)
+					if(!R)
+						return
+					else
+						R.reaction_obj(A, R.volume*volume_modifier)
 	return
 
 /datum/reagents/proc/add_reagent_list(list/list_reagents, list/data=null) // Like add_reagent but you can enter a list. Format it like this: list("toxin" = 10, "beer" = 15)

code/modules/reagents/newchem/pyro.dm

@@ -293,7 +293,7 @@ datum/reagent/blackpowder/reaction_turf(var/turf/T, var/volume) //oh shit
 	required_reagents = list("potassium" = 1, "sugar" = 1, "phosphorus" = 1)
 	result_amount = 1
 	mix_message = "The mixture quickly turns into a pall of smoke!"
-	var/forbidden_reagents = list("sugar", "phosphorus", "potassium") //Do not transfer this stuff through smoke.
+	var/forbidden_reagents = list("sugar", "phosphorus", "potassium", "stimulants") //Do not transfer this stuff through smoke.
 
 /datum/chemical_reaction/smoke/on_reaction(var/datum/reagents/holder, var/created_volume)
 	for(var/f_reagent in forbidden_reagents)
@@ -325,7 +325,7 @@ datum/reagent/blackpowder/reaction_turf(var/turf/T, var/volume) //oh shit
 	min_temp = 374
 	secondary = 1
 	result_amount = 1
-	forbidden_reagents = list()
+	forbidden_reagents = list("stimulants")
 	mix_sound = null
 
 /datum/reagent/sonic_powder

code/modules/surgery/organs/blood.dm

@@ -190,7 +190,9 @@ var/const/BLOOD_VOLUME_SURVIVE = 122
 
 	if(src.species.exotic_blood)
 		vessel.remove_reagent(species.exotic_blood,amm)
-		vessel.reaction(T, TOUCH, amm)
+		if(vessel.total_volume)
+			var/fraction = amm / vessel.total_volume
+			vessel.reaction(T, TOUCH, fraction)
 		return
 
 	else