Cases relied upon by appellant, in which there was an insufficient showing that the blood sample had come from the body of the deceased in question, are distinguishable from the instant factual situation. The cases cited by appellant, to wit: People v. Smith, 55 Cal.App. 324 [ 203 P. 816]; American Mutual etc. Co. v. Industrial Acc. Com., 78 Cal.App.2d 493 [ 178 P.2d 40]; McGowan v. City of Los Angeles, 100 Cal.App.2d 386 [ 223 P.2d 862, 21 A.L.R.2d 1206]; Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782 [ 251 P.2d 349]; Nesje v. Metropolitan Coach Lines, 140 Cal.App.2d 807 [ 295 P.2d 979]; Madden v. Madden, 160 Cal.App.2d 422 [ 325 P.2d 538], are readily distinguishable from the facts in the instant situation. Here, it was admitted by the pleadings that Donald Graham Osborn was the driver of the car.

The crux of such a claim is that the expert testimony relies on tests of a sample not adequately shown to reflect or represent the item in question. (Dobson v. Industrial Acc. Com. (1952) 114 Cal.App.2d 782, 783 (Dobson); AmericanMut. etc. Co. v. Ind. Acc. Com. (1947) 78 Cal.App.2d 493, 496-497 (American); see County of Sonoma v. Graham (1986) 187 Cal.App.3d 1439, 1448-1449.) "In a chain of custody claim, '"[t]he burden on the party offering the evidence is to show to the satisfaction of the trial court that, taking all the circumstances into account including the ease or difficulty with which the particular evidence could have been altered, it is reasonably certain that there was no alteration. [¶] The requirement of reasonable certainty is not met when some vital link in the chain of possession is not accounted for, because then it is as likely as not that the evidence analyzed was not the evidence originally received.

In light of this testimony and the additional uncontradicted testimony that the surgery was performed with due care, it would have been improper speculation for the jury to infer the injury should have been apparent to a careful surgeon. ( Dobson v. Industrial Acc. Com. (1952) 114 Cal.App.2d 782, 786-787 [ 251 P.2d 349].) (6) Finally, plaintiff relies on his own testimony that defendant said to plaintiff, "He [i.e., defendant] blamed himself for me being back in there [the hospital for a second time]."

Appellant further argues that the chain of possession was not properly established prior to admission of the check fragment in evidence, in negation of any possibility of alteration between the time the evidence in question was first secured and its production in court. ( People v. Riser, 47 Cal.2d 566, 580-581 [ 305 P.2d 1] [fingerprints on a glass]; also Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782, 785 [ 251 P.2d 349] [a blood sample]; McGowan v. City of Los Angeles, 100 Cal.App.2d 386, 389-392 [ 223 P.2d 862, 21 A.L.R.2d 1206] [a blood alcohol analysis]; People v. Smith, 55 Cal.App. 324, 330-331 [ 203 P. 816] [stomach analysis].) We find it unnecessary to decide the novel and difficult question whether the exclusionary rule should be extended to evidence obtained by an unlawful search made in another state by officers of that state, or whether the check fragment was sufficiently identified (although we note that the testifying officer positively identified the check fragment as the one which he had found).

Left to such speculation the court must exclude the evidence. (See Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782, 785 [ 251 P.2d 349]; McGowan v. Los Angeles, 100 Cal.App.2d 386, 389-392 [ 223 P.2d 862, 21 A.L.R.2d 1206]; People v. Smith, 55 Cal.App. 324, 327-329 [ 203 P. 816]; Novak v. District of Columbia, 160 F.2d 588 [ 82 App.D.C. 95].) [16] Conversely, when it is the barest speculation that there was tampering, it is proper to admit the evidence and let what doubt remains go to its weight. (See People v. Tomasovich, 56 Cal.App. 520, 529 [ 206 P. 119]; State v. Smith (Mo.), 222 S.W. 455, 458-459.)

It is not our office here to conjure up a plausible or conceivable reason to justify the conclusion that the ordinance had a reasonable relation to the protection of the public health, safety, morals or general welfare of the public. (8) The courts take judicial knowledge of the effect on human beings of the consumption of alcoholic beverages ( Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782, 786 [ 251 P.2d 349]; Dobson v. Dobson, 86 Cal.App.2d 13, 14-15 [ 193 P.2d 794]), and it is common knowledge that the drinking of alcoholic beverages "ordinarily loosens the normal inhibitions and restraints." ( State v. Rand, 238 Iowa 250 [ 25 N.W.2d 800, 811, 170 A.L.R. 289, 304].)

Left to such speculation the court must exclude the evidence. (See Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782, 785 [ 251 P.2d 349]; McGowan v. Los Angeles, 100 Cal.App.2d 386, 389-392 [ 223 P.2d 862, 21 A.L.R.2d 1206]; People v. Smith, 55 Cal.App. 324, 327-329 [ 203 P. 816]; Novak v. District of Columbia, 160 F.2d 588 [82 App. D.C. 95].) [4] Conversely, when it is the barest speculation that there was tampering, it is proper to admit the evidence and let what doubt remains go to its weight. (See People v. Tomasovich, 56 Cal.App. 520, 529 [ 206 P. 119]; State v. Smith (Mo.), 222 S.W. 455, 458-459.)

But such a result can be sustained only if there is some evidence to support it. Mere speculation as to probabilities will not support a finding of fact ( Dodson v. Industrial Acc. Com., 114 Cal.App.2d 782 [ 251 P.2d 349]). Judgment reversed.

[3] Of course, findings may not be lawfully based on mere suspicion or speculation. ( Reese v. Smith, 9 Cal.2d 324 [ 70 P.2d 933]; Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782 [ 251 P.2d 349]; McKellar v. Pendergast, 68 Cal.App.2d 485 [ 156 P.2d 950].) [4] Appellant also properly points out that "`If there be two inferences equally reasonable and equally susceptible of being drawn from the proved facts, the one favoring fair dealing and the other favoring corrupt practice, it is the express duty of court or jury to draw the inference favorable to fair dealing.'"

There was no further evidence as to a foundation for the admission of the document. In Dobson v. Industrial Acc. Com., 114 Cal.App.2d 782 [ 251 P.2d 349], it was said (quoting from syllabus 2) that "Testimony that a blood sample contains alcohol without some evidence to show that the blood is that of the person charged with being intoxicated amounts to no proof at all that he was." In Everts v. Matteson, 68 Cal.App.2d 577 [ 157 P.2d 651], it was held that a communication from a person who had been employed to appraise realty was not a corporate record, under Civil Code, section 371, nor was it admissible in evidence merely because the employer had it among his papers.