NORTONI, J.
This is a suit for damages accrued on account of a breach of contract. Plaintiffs recovered and defendant prosecutes the appeal.
The damages sued for were occasioned by means of the overflow of certain fields whereby crops were destroyed and certain top soil washed from a portion of the cultivated lands. Besides this, there is a question made with respect to a right to recover compensation for rebuilding a fence which it appears belonged to defendant, but-was washed over upon plaintiffs’ cultivated lands.
The lands overflowed are situated adjacent to Saline creek. Plaintiffs’ vendor and assignor, Bernard S. Pratte, formerly owned these lands and, on the 28th day of August, 1905, entered into the written contract with defendant railroad company which is here sued upon. -By this contract, Pratte agreed to convey to the railroad company a right of way for its railroad across such lands along and adjacent to Saline creek, and in consideration therefor defendant railroad company agreed and undertook to construct a solid embankment along the line referred to in the contract for its railroad, which was to be built above high-water mark so as to protect the lands from overflow, and Pratte was accorded the right to join certain other levees thereto. The contract authorized the railroad company to take immediate possession of the right of way referred to, for the purpose of constructing its railroad thereon, and this it did. The railroad was completed some time in the year 1906, but it appears *631the embankment was not built as required by tbe contract—that is, np to tbe high-water mark. On tbe contrary, tbe evidence tends to prove that it was built several feet below that, and because of this, tbe overflow from Saline creek passed over tbe railroad embankment in tbe spring of 1910 and inundated Pratte’s fields, so as to destroy bis growing crops thereon and to wash away a considerable amount of tbe top soil on a portion of bis land. Among other things, this flood dislodged and removed a large portion of tbe railroad right of way wire fence from its position, rolled it up, and deposited it in tbe fields. In order to protect bis remaining crops and possessions and to tbe end of mitigating damages thereto, Pratte removed tbe fence from where it was deposited in tbe fields on bis lands and rebuilt it along tbe right of way, at an expenditure of about $260. One of tbe items of damages sued for relates to this matter.
By a general warranty deed,.dated on tbe 25th day of July, 1910, Bernard S. Pratte and wife, with whom tbe contract was originally entered into by defendant, conveyed tbe lands involved to plaintiffs, Patrick H. Coffman, Augusta C. Rond and Robert A. Brown. Although this deed is of date July 25, 1910, it appears to have been acknowledged and delivered on tbe following day—that is, July 26, 1910—and on tbe same day Pratte, tbe grantor, assigned tbe contract here sued upon to these plaintiffs. From this it appears that plaintiffs succeeded to both tbe title of Pratte and wife in tbe lands and to bis rights under tbe contract as well. A couple of weeks afterward—that is to say, on tbe 10th day of August, 1910—Bernard S. Pratte formally executed to plaintiffs a written assignment of bis right of action for damages, past, present and future, and for such damages as bad accrued to him against defendant on account of tbe breach of said contract, and all rights of action thereunder or thereabout, to these plaintiffs. Plaintiffs thereupon insti*632tuted this suit for damages, and, as before said, recovered against defendant as for a breach of the contract, in that, though it had constructed its railroad and embankment in 1906', it wholly failed to érect the embankment, as required by the contract, above the high-water mark along Saline creek, and because of this the fields were inundated through an overflow from the creek and the damages sued for suffered.
It appears that, though "Pratte assigned his right of action for all damages suffered by the overflow and because of the breach of the contract to construct a solid embankment above the high-water mark to these plaintiffs, as above stated, he retains some interest in the proceeds of the recovery. "What his interest therein is does not definitely appear, but the case concedes that he is still interested therein in some amount.
It is first argued the judgment should be reversed for the reason the suit is not brought in the name of the real party in interest. The suit proceeds in the name of the three plaintiffs who succeeded to P'ratte’s rights in the lands by virtue of his deed and who succeeded to the right of action for damages under the written assignment thereof above described. Obviously there is no merit in this argument, for the subject-matter of the assignment is a mere chose in action arising out of contract, and the assignee may sue thereon, though the title were passed to him for no other purpose than that of collection. Moreover, if Pratte is interested in a portion of the recovery, these plaintiffs are to be regarded as the trustees of an express trust under the code provision, and the suit is properly brought by them, and it remain for them to account to Pratte. Defendant is immune from further prosecution on account of the same cause of action as that involved in the assignment here. [See West Plains Bank v. Edwards, 84 Mo. App. 462; Young v. Hudson, 99 Mo. 102, 12 S. W. 632; Springfield, to use, v. Weaver, 137 Mo. 650; 37 S. W. 509; 39 S. W. 276.]
*633The contract sued upon stipulates that “the railroad shall he built above the high-water mark.” Plaintiffs introduced evidence tending to show the situation of the land, its liability to overflow from Saline creek, and the point regarded in the community as high-water mark. Among other things, they were permitted to show that defendant’s agent, together with plaintiff, went over the right of way immediately before the contract was signed and ascertained the high-water mark by examining the same on certain trees where such high-water mark was pointed out and located. It is argued this evidence was incompetent, in that it tended to vary the terms of a written contract, for it is said the meaning of-the words “high-water mark” indicates the point at which high water reaches when no freshets occur. But we are not persuaded to this view. The court received this evidence and submitted the question of the high-water mark to the jury on the theory that these words in the contract imported some ambiguity. There was no error in this, for though it be true that one may not introduce parol evidence to vary or contradict the terms of a written contract, he may do so to dispel an ambiguity therein. But in so doing, it is, of course, not competent to give evidence directly as to what the parties intended. However, enough of the facts and circumstances surrounding the parties at the time the contract was made may be shown as is essential to place the court and jury in the situation they then occupied and thus indue the tribunal trying the fact with the knowledge possessed by the contracting parties in order to ascertain the true intention. The intention of the parties is the matter to be sought for in giving judgment upon every contract in dispute, and to ascertain this it is frequently essential to consider the surrounding facts and circumstances as introduced in evidence here. [See Ellis v. Harrison, 104 Mo. 270, 16 S. W. 198; Laclede Const. Co. v. Moss Tie Co., 185 Mo. 25, 62, 84 S. W. *63476.] In this connection it_ is to be said the circumstances under which the contract is made and the object in view should be considered in giving meaning to doubtful terms. [See Nordyke, etc. Co. v. Kehlor, 155 Mo. 643, 56 S. W. 287.] Here the contract reveals on its face that it was intended the railroad embankment should be built high enough to protect plaintiffs ’ lands from overflow. It was for such protection alone Pratte agreed to convey the railroad right of way free of other charges therefor: Such was the entire consideration moving between the parties. Obviously a railroad embankment constructed no higher than the high-water mark when no freshet was present in Saline creek would avail nothing of value as consideration for the right of way. The contract provided Pratte should have the right to connect other levees with the railroad embankment which was to be built above the high-water mark. It is entirely clear that it was competent to show by the water marks on the trees where the high-water mark was and that defendant’s agent who made the contract for it examined such trees and ascertained the fact in connection with Pratte at the time. Such is merely identifying the subject-matter of which this term of the contract relates.
It is earnestly insisted that the court erred in its instruction on the measure of damages, but the argument is without merit. It appears from the instructions that, in so far as the loss of growing crops on the land is concerned, the court told the jury plaintiffs were entitled to be compensated according to the value of the crops destroyed which were then standing in the field, and such is the correct rule on the subject. [See Pace v. St. Louis, etc. R. Co., 174 Mo. App. 227, 156 S. W. 746; Hunt v. St. Louis, etc. R. Co., 126 Mo. App. 261, 103 S. W. 133; Carter v. Wabash R. Co., 128 Mo. App. 57, 106 S. W. 611.]
The evidence reveals that certain top soil was washed away from a goodly portion of the cultivated *635land and that such caused its value to depreciate. As to this the court informed the jury that the damage should he determined by ascertaining the difference in value of the land before and after the injury. Such is the correct rule of damages on this question, for the injury thus suffered is to the inheritance. [See Wiggins v. St. Louis, Memphis, etc. R. Co., 119 Mo. App. 492, 95 S. W. 311; White v. Stoner, 18 Mo. App. 540; Carter v. Wabash R. Co., 128 Mo. App. 57, 106 S. W. 611; Gates v. Chicago & A. R. Co., 44 Mo. App. 488, 495.]
It appears that defendant had constructed a right of way fence of posts and wire along on Pratte’s land but designed to inclose its railroad right of way and sever it from the farm. The inundation of the lands resulting from the overflow of Saline creek and because defendant failed to construct the embankment above high-water mark dislodged this fence from its position and deposited it in the fields. When the flood abated, Platte went about clearing his field of debris and encountered this fence rolled up and tangled together. He employed labor and removed it from the field and reset it in position, but omitted to first give notice to defendant to do so. This proceeding entailed an expense of- $260, and plaintiff was permitted to recover from defendant therefor. In connection with that matter, the court gave instruction number 3a, as follows:
‘1 The court instructs the jury that, if your finding be for plaintiffs, you will in fixing the damages, if any, which accrued to the fence alleged to have been torn away, allow to plaintiff the fair and reasonable worth and value, at the time and place of the work and labor expended in removing said fence from the place to which it had been carried by said flood, and of repairing and re-building said fence, at the original location.”
*636It is argued that this was error. The argument concerning this matter proceeds on the theory that plaintiff was permitted to recover the value of the fence so washed away as if the fence belonged to him. Obviously nothing like this appears in the record and the entire argument in the brief concerning it is wholly beside the case. From a reading of the instruction above copied, it appears plaintiff was permitted to recover no more than the fair and reasonable value at the time and place of the work and labor expended in removing the fence from the place in the field to which it had been carried by the flood and of repairing and rebuilding it at the point of original location. Obviously it was plaintiff’s duty to mitigate the damages, if within his power to do so. Had the fence remained in the field, his premises and other crops would have been exposed to incursion of cattle from without and he be denied the use of the land whereon the fence lay entangled with debris. There is no suggestion in the briefs of an exorbitant charge concerning this matter and no one can doubt the duty of defendant to replace the fence after it was washed away. We believe it was well enough to permit plaintiff to recover in this suit for the amount he expended in thus removing the fence from his land and replacing it in its proper position, and especially is this true when it is remembered that the law devolved the duty upon plaintiff to act promptly with a view of mitigating the damage which might ensue for defendant’s benefit. But, in any view of the case, as the fence was reconstructed where the railroad fencing statute required defendant to erect and maintain it, and as there is no suggestion that the charge therefor was unreasonable on the part of plaintiff, we believe that no possible error affecting' the merits of the action against defendant can be predicated upon this matter. It is only for errors materially affecting the merits of the case, against the substantial rights of an appellant, that judgments *637should be reversed on appeal under our statute. [See Shinn v. United Rys. Co., 248 Mo. 173, 154 S. W. 103.]
There are several arguments put forward in the brief, but we regard all of them that merit discussion as fully answered by what has been said. We have examined the record with care and considered all of the points made, but see no reversible error therein. The case was well instructed by the court and no error appears in refusing instructions requested by defendant.
The judgment should be affirmed. It is so ordered.
Reynolds, P. J., and Allen, J., concur.